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<div class="subTitle">com.sleepycat.persist</div>
<h2 title="Class SecondaryIndex" class="title">Class SecondaryIndex&lt;SK,PK,E&gt;</h2>
</div>
<div class="contentContainer">
<ul class="inheritance">
<li>java.lang.Object</li>
<li>
<ul class="inheritance">
<li>com.sleepycat.persist.SecondaryIndex&lt;SK,PK,E&gt;</li>
</ul>
</li>
</ul>
<div class="description">
<ul class="blockList">
<li class="blockList">
<dl>
<dt>All Implemented Interfaces:</dt>
<dd><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;SK,E&gt;</dd>
</dl>
<hr>
<br>
<pre>public class <span class="typeNameLabel">SecondaryIndex&lt;SK,PK,E&gt;</span>
extends java.lang.Object</pre>
<div class="block">The secondary index for an entity class and a secondary key.
<p><code>SecondaryIndex</code> objects are thread-safe. Multiple threads may
safely call the methods of a shared <code>SecondaryIndex</code> object.</p>
<p><code>SecondaryIndex</code> implements <a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist"><code>EntityIndex</code></a> to map the
secondary key type (SK) to the entity type (E). In other words, entities
are accessed by secondary key values.</p>
<p>The <a href="../../../com/sleepycat/persist/model/SecondaryKey.html" title="annotation in com.sleepycat.persist.model"><code>SecondaryKey</code></a> annotation may be used to define a secondary key
as shown in the following example.</p>
<pre class="code">
@Entity
class Employee {
@PrimaryKey
long id;
@SecondaryKey(relate=MANY_TO_ONE)
String department;
String name;
private Employee() {}
}</pre>
<p>Before obtaining a <code>SecondaryIndex</code>, the <a href="../../../com/sleepycat/persist/PrimaryIndex.html" title="class in com.sleepycat.persist"><code>PrimaryIndex</code></a> must
be obtained for the entity class. To obtain the <code>SecondaryIndex</code> call
<a href="../../../com/sleepycat/persist/EntityStore.html#getSecondaryIndex-com.sleepycat.persist.PrimaryIndex-java.lang.Class-java.lang.String-"><code>EntityStore.getSecondaryIndex</code></a>, passing
the primary index, the secondary key class and the secondary key name. For
example:</p>
<pre class="code">
EntityStore store = new EntityStore(...);
<code>PrimaryIndex&lt;Long, Employee&gt;</code> primaryIndex =
store.getPrimaryIndex(Long.class, Employee.class);
<code>SecondaryIndex&lt;String, Long, Employee&gt;</code> secondaryIndex =
store.getSecondaryIndex(primaryIndex, String.class, "department");</pre>
<p>Since <code>SecondaryIndex</code> implements the <a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist"><code>EntityIndex</code></a>
interface, it shares the common index methods for retrieving and deleting
entities, opening cursors and using transactions. See <a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist"><code>EntityIndex</code></a>
for more information on these topics.</p>
<p><code>SecondaryIndex</code> does <em>not</em> provide methods for inserting
and updating entities. That must be done using the <a href="../../../com/sleepycat/persist/PrimaryIndex.html" title="class in com.sleepycat.persist"><code>PrimaryIndex</code></a>.</p>
<p>Note that a <code>SecondaryIndex</code> has three type parameters <code>&lt;SK,
PK, E&gt;</code> or in the example <code>&lt;String, Long, Employee&gt;</code> while a <a href="../../../com/sleepycat/persist/PrimaryIndex.html" title="class in com.sleepycat.persist"><code>PrimaryIndex</code></a> has only two type parameters <code>&lt;PK, E&gt;</code> or <code>&lt;Long,
Employee&gt;</code>. This is because a <code>SecondaryIndex</code> has an extra level of
mapping: It maps from secondary key to primary key, and then from primary
key to entity. For example, consider this entity:</p>
<div><table class="code" border="1" summary="">
<tr><th>ID</th><th>Department</th><th>Name</th></tr>
<tr><td>1</td><td>Engineering</td><td>Jane Smith</td></tr>
</table></div>
<p>The <a href="../../../com/sleepycat/persist/PrimaryIndex.html" title="class in com.sleepycat.persist"><code>PrimaryIndex</code></a> maps from id directly to the entity, or from
primary key 1 to the "Jane Smith" entity in the example. The <code>SecondaryIndex</code> maps from department to id, or from secondary key
"Engineering" to primary key 1 in the example, and then uses the <code>PrimaryIndex</code> to map from the primary key to the entity.</p>
<p>Because of this extra type parameter and extra level of mapping, a <code>SecondaryIndex</code> can provide more than one mapping, or view, of the entities
in the primary index. The main mapping of a <code>SecondaryIndex</code> is to
map from secondary key (SK) to entity (E), or in the example, from the
String department key to the Employee entity. The <code>SecondaryIndex</code>
itself, by implementing <code>EntityIndex&lt;SK, E&gt;</code>, provides this
mapping.</p>
<p>The second mapping provided by <code>SecondaryIndex</code> is from secondary
key (SK) to primary key (PK), or in the example, from the String department
key to the Long id key. The <a href="../../../com/sleepycat/persist/SecondaryIndex.html#keysIndex"><code>keysIndex</code></a> method provides this
mapping. When accessing the keys index, the primary key is returned rather
than the entity. When only the primary key is needed and not the entire
entity, using the keys index is less expensive than using the secondary
index because the primary index does not have to be accessed.</p>
<p>The third mapping provided by <code>SecondaryIndex</code> is from primary key
(PK) to entity (E), for the subset of entities having a given secondary key
(SK). This mapping is provided by the <a href="../../../com/sleepycat/persist/SecondaryIndex.html#subIndex-SK-"><code>subIndex(SK)</code></a> method. A
sub-index is convenient when you are interested in working with the subset
of entities having a particular secondary key value, for example, all
employees in a given department.</p>
<p>All three mappings, along with the mapping provided by the <a href="../../../com/sleepycat/persist/PrimaryIndex.html" title="class in com.sleepycat.persist"><code>PrimaryIndex</code></a>, are shown using example data in the <a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist"><code>EntityIndex</code></a>
interface documentation. See <a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist"><code>EntityIndex</code></a> for more information.</p>
<p>Note that when using an index, keys and values are stored and retrieved
by value not by reference. In other words, if an entity object is stored
and then retrieved, or retrieved twice, each object will be a separate
instance. For example, in the code below the assertion will always
fail.</p>
<pre class="code">
MyKey key = ...;
MyEntity entity1 = index.get(key);
MyEntity entity2 = index.get(key);
assert entity1 == entity2; // always fails!
</pre>
<h3>One-to-One Relationships</h3>
<p>A <a href="../../../com/sleepycat/persist/model/Relationship.html#ONE_TO_ONE"><code>ONE_TO_ONE</code></a> relationship, although less
common than other types of relationships, is the simplest type of
relationship. A single entity is related to a single secondary key value.
For example:</p>
<pre class="code">
@Entity
class Employee {
@PrimaryKey
long id;
@SecondaryKey(relate=ONE_TO_ONE)
String ssn;
String name;
private Employee() {}
}
<code>SecondaryIndex&lt;String, Long, Employee&gt;</code> employeeBySsn =
store.getSecondaryIndex(primaryIndex, String.class, "ssn");</pre>
<p>With a <a href="../../../com/sleepycat/persist/model/Relationship.html#ONE_TO_ONE"><code>ONE_TO_ONE</code></a> relationship, the
secondary key must be unique; in other words, no two entities may have the
same secondary key value. If an attempt is made to store an entity having
the same secondary key value as another existing entity, a <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je"><code>DatabaseException</code></a> will be thrown.</p>
<p>Because the secondary key is unique, it is useful to lookup entities by
secondary key using <a href="../../../com/sleepycat/persist/EntityIndex.html#get-K-"><code>EntityIndex.get(K)</code></a>. For example:</p>
<pre class="code">
Employee employee = employeeBySsn.get(mySsn);</pre>
<h3>Many-to-One Relationships</h3>
<p>A <a href="../../../com/sleepycat/persist/model/Relationship.html#MANY_TO_ONE"><code>MANY_TO_ONE</code></a> relationship is the most
common type of relationship. One or more entities is related to a single
secondary key value. For example:</p>
<pre class="code">
@Entity
class Employee {
@PrimaryKey
long id;
@SecondaryKey(relate=MANY_TO_ONE)
String department;
String name;
private Employee() {}
}
<code>SecondaryIndex&lt;String, Long, Employee&gt;</code> employeeByDepartment =
store.getSecondaryIndex(primaryIndex, String.class, "department");</pre>
<p>With a <a href="../../../com/sleepycat/persist/model/Relationship.html#MANY_TO_ONE"><code>MANY_TO_ONE</code></a> relationship, the
secondary key is not required to be unique; in other words, more than one
entity may have the same secondary key value. In this example, more than
one employee may belong to the same department.</p>
<p>The most convenient way to access the employees in a given department is
by using a sub-index. For example:</p>
<pre class="code">
<code>EntityIndex&lt;Long, Entity&gt;</code> subIndex = employeeByDepartment.subIndex(myDept);
<code>EntityCursor&lt;Employee&gt;</code> cursor = subIndex.entities();
try {
for (Employee entity : cursor) {
// Do something with the entity...
}
} finally {
cursor.close();
}</pre>
<h3>One-to-Many Relationships</h3>
<p>In a <a href="../../../com/sleepycat/persist/model/Relationship.html#ONE_TO_MANY"><code>ONE_TO_MANY</code></a> relationship, a single
entity is related to one or more secondary key values. For example:</p>
<pre class="code">
@Entity
class Employee {
@PrimaryKey
long id;
@SecondaryKey(relate=ONE_TO_MANY)
Set&lt;String&gt; emailAddresses = new HashSet&lt;String&gt;;
String name;
private Employee() {}
}
<code>SecondaryIndex&lt;String, Long, Employee&gt;</code> employeeByEmail =
store.getSecondaryIndex(primaryIndex, String.class, "emailAddresses");</pre>
<p>With a <a href="../../../com/sleepycat/persist/model/Relationship.html#ONE_TO_MANY"><code>ONE_TO_MANY</code></a> relationship, the
secondary key must be unique; in other words, no two entities may have the
same secondary key value. In this example, no two employees may have the
same email address. If an attempt is made to store an entity having the
same secondary key value as another existing entity, a <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je"><code>DatabaseException</code></a> will be thrown.</p>
<p>Because the secondary key is unique, it is useful to lookup entities by
secondary key using <a href="../../../com/sleepycat/persist/EntityIndex.html#get-K-"><code>EntityIndex.get(K)</code></a>. For example:</p>
<pre class="code">
Employee employee = employeeByEmail.get(myEmailAddress);</pre>
<p>The secondary key field for a <a href="../../../com/sleepycat/persist/model/Relationship.html#ONE_TO_MANY"><code>ONE_TO_MANY</code></a> relationship must be an array or collection type. To access
the email addresses of an employee, simply access the collection field
directly. For example:</p>
<pre class="code">
Employee employee = primaryIndex.get(1); // Get the entity by primary key
employee.emailAddresses.add(myNewEmail); // Add an email address
primaryIndex.putNoReturn(1, employee); // Update the entity</pre>
<h3>Many-to-Many Relationships</h3>
<p>In a <a href="../../../com/sleepycat/persist/model/Relationship.html#MANY_TO_MANY"><code>MANY_TO_MANY</code></a> relationship, one
or more entities is related to one or more secondary key values. For
example:</p>
<pre class="code">
@Entity
class Employee {
@PrimaryKey
long id;
@SecondaryKey(relate=MANY_TO_MANY)
Set&lt;String&gt; organizations = new HashSet&lt;String&gt;;
String name;
private Employee() {}
}
<code>SecondaryIndex&lt;String, Long, Employee&gt;</code> employeeByOrganization =
store.getSecondaryIndex(primaryIndex, String.class, "organizations");</pre>
<p>With a <a href="../../../com/sleepycat/persist/model/Relationship.html#MANY_TO_MANY"><code>MANY_TO_MANY</code></a> relationship, the
secondary key is not required to be unique; in other words, more than one
entity may have the same secondary key value. In this example, more than
one employee may belong to the same organization.</p>
<p>The most convenient way to access the employees in a given organization
is by using a sub-index. For example:</p>
<pre class="code">
<code>EntityIndex&lt;Long, Entity&gt;</code> subIndex = employeeByOrganization.subIndex(myOrg);
<code>EntityCursor&lt;Employee&gt;</code> cursor = subIndex.entities();
try {
for (Employee entity : cursor) {
// Do something with the entity...
}
} finally {
cursor.close();
}</pre>
<p>The secondary key field for a <a href="../../../com/sleepycat/persist/model/Relationship.html#MANY_TO_MANY"><code>MANY_TO_MANY</code></a> relationship must be an array or collection type. To access
the organizations of an employee, simply access the collection field
directly. For example:</p>
<pre class="code">
Employee employee = primaryIndex.get(1); // Get the entity by primary key
employee.organizations.remove(myOldOrg); // Remove an organization
primaryIndex.putNoReturn(1, employee); // Update the entity</pre>
<h3>Foreign Key Constraints for Related Entities</h3>
<p>In all the examples above the secondary key is treated only as a simple
value, such as a <code>String</code> department field. In many cases, that is
sufficient. But in other cases, you may wish to constrain the secondary
keys of one entity class to be valid primary keys of another entity
class. For example, a Department entity may also be defined:</p>
<pre class="code">
@Entity
class Department {
@PrimaryKey
String name;
String missionStatement;
private Department() {}
}</pre>
<p>You may wish to constrain the department field values of the Employee
class in the examples above to be valid primary keys of the Department
entity class. In other words, you may wish to ensure that the department
field of an Employee will always refer to a valid Department entity.</p>
<p>You can implement this constraint yourself by validating the department
field before you store an Employee. For example:</p>
<pre class="code">
<code>PrimaryIndex&lt;String, Department&gt;</code> departmentIndex =
store.getPrimaryIndex(String.class, Department.class);
void storeEmployee(Employee employee) throws DatabaseException {
if (departmentIndex.contains(employee.department)) {
primaryIndex.putNoReturn(employee);
} else {
throw new IllegalArgumentException("Department does not exist: " +
employee.department);
}
}</pre>
<p>Or, instead you could define the Employee department field as a foreign
key, and this validation will be done for you when you attempt to store the
Employee entity. For example:</p>
<pre class="code">
@Entity
class Employee {
@PrimaryKey
long id;
@SecondaryKey(relate=MANY_TO_ONE, relatedEntity=Department.class)
String department;
String name;
private Employee() {}
}</pre>
<p>The <code>relatedEntity=Department.class</code> above defines the department
field as a foreign key that refers to a Department entity. Whenever a
Employee entity is stored, its department field value will be checked to
ensure that a Department entity exists with that value as its primary key.
If no such Department entity exists, then a <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je"><code>DatabaseException</code></a> is
thrown, causing the transaction to be aborted (assuming that transactions
are used).</p>
<p>This begs the question: What happens when a Department entity is deleted
while one or more Employee entities have department fields that refer to
the deleted department's primary key? If the department were allowed to be
deleted, the foreign key constraint for the Employee department field would
be violated, because the Employee department field would refer to a
department that does not exist.</p>
<p>By default, when this situation arises the system does not allow the
department to be deleted. Instead, a <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je"><code>DatabaseException</code></a> is thrown,
causing the transaction to be aborted. In this case, in order to delete a
department, the department field of all Employee entities must first be
updated to refer to a different existing department, or set to null. This
is the responsibility of the application.</p>
<p>There are two additional ways of handling deletion of a Department
entity. These alternatives are configured using the <a href="../../../com/sleepycat/persist/model/SecondaryKey.html#onRelatedEntityDelete--"><code>SecondaryKey.onRelatedEntityDelete()</code></a> annotation property. Setting this
property to <a href="../../../com/sleepycat/persist/model/DeleteAction.html#NULLIFY"><code>DeleteAction.NULLIFY</code></a> causes the Employee department
field to be automatically set to null when the department they refer to is
deleted. This may or may not be desirable, depending on application
policies. For example:</p>
<pre class="code">
@Entity
class Employee {
@PrimaryKey
long id;
<code>@SecondaryKey(relate=MANY_TO_ONE, relatedEntity=Department.class,
onRelatedEntityDelete=NULLIFY)</code>
String department;
String name;
private Employee() {}
}</pre>
<p>The <a href="../../../com/sleepycat/persist/model/DeleteAction.html#CASCADE"><code>DeleteAction.CASCADE</code></a> value, on the other hand, causes the
Employee entities to be automatically deleted when the department they refer
to is deleted. This is probably not desirable in this particular example,
but is useful for parent-child relationships. For example:</p>
<pre class="code">
@Entity
class Order {
@PrimaryKey
long id;
String description;
private Order() {}
}
@Entity
class OrderItem {
@PrimaryKey
long id;
<code>@SecondaryKey(relate=MANY_TO_ONE, relatedEntity=Order.class,
onRelatedEntityDelete=CASCADE)</code>
long orderId;
String description;
private OrderItem() {}
}</pre>
<p>The OrderItem orderId field refers to its "parent" Order entity. When an
Order entity is deleted, it may be useful to automatically delete its
"child" OrderItem entities.</p>
<p>For more information, see <a href="../../../com/sleepycat/persist/model/SecondaryKey.html#onRelatedEntityDelete--"><code>SecondaryKey.onRelatedEntityDelete()</code></a>.</p>
<h3>One-to-Many versus Many-to-One for Related Entities</h3>
<p>When there is a conceptual Many-to-One relationship such as Employee to
Department as illustrated in the examples above, the relationship may be
implemented either as Many-to-One in the Employee class or as One-to-Many in
the Department class.</p>
<p>Here is the Many-to-One approach.</p>
<pre class="code">
@Entity
class Employee {
@PrimaryKey
long id;
@SecondaryKey(relate=MANY_TO_ONE, relatedEntity=Department.class)
String department;
String name;
private Employee() {}
}
@Entity
class Department {
@PrimaryKey
String name;
String missionStatement;
private Department() {}
}</pre>
<p>And here is the One-to-Many approach.</p>
<pre class="code">
@Entity
class Employee {
@PrimaryKey
long id;
String name;
private Employee() {}
}
@Entity
class Department {
@PrimaryKey
String name;
String missionStatement;
@SecondaryKey(relate=ONE_TO_MANY, relatedEntity=Employee.class)
Set&lt;Long&gt; employees = new HashSet&lt;Long&gt;;
private Department() {}
}</pre>
<p>Which approach is best? The Many-to-One approach better handles large
number of entities on the to-Many side of the relationship because it
doesn't store a collection of keys as an entity field. With Many-to-One a
Btree is used to store the collection of keys and the Btree can easily
handle very large numbers of keys. With One-to-Many, each time a related
key is added or removed the entity on the One side of the relationship,
along with the complete collection of related keys, must be updated.
Therefore, if large numbers of keys may be stored per relationship,
Many-to-One is recommended.</p>
<p>If the number of entities per relationship is not a concern, then you may
wish to choose the approach that is most natural in your application data
model. For example, if you think of a Department as containing employees
and you wish to modify the Department object each time an employee is added
or removed, then you may wish to store a collection of Employee keys in the
Department object (One-to-Many).</p>
<p>Note that if you have a One-to-Many relationship and there is no related
entity, then you don't have a choice -- you have to use One-to-Many because
there is no entity on the to-Many side of the relationship where a
Many-to-One key could be defined. An example is the Employee to email
addresses relationship discussed above:</p>
<pre class="code">
@Entity
class Employee {
@PrimaryKey
long id;
@SecondaryKey(relate=ONE_TO_MANY)
Set&lt;String&gt; emailAddresses = new HashSet&lt;String&gt;;
String name;
private Employee() {}
}</pre>
<p>For sake of argument imagine that each employee has thousands of email
addresses and employees frequently add and remove email addresses. To
avoid the potential performance problems associated with updating the
Employee entity every time an email address is added or removed, you could
create an EmployeeEmailAddress entity and use a Many-to-One relationship as
shown below:</p>
<pre class="code">
@Entity
class Employee {
@PrimaryKey
long id;
String name;
private Employee() {}
}
@Entity
class EmployeeEmailAddress {
@PrimaryKey
String emailAddress;
@SecondaryKey(relate=MANY_TO_ONE, relatedEntity=Employee.class)
long employeeId;
private EmployeeEmailAddress() {}
}</pre>
<h3>Key Placement with Many-to-Many for Related Entities</h3>
<p>As discussed in the section above, one drawback of a to-Many relationship
(One-to-Many was discussed above and Many-to-Many is discussed here) is that
it requires storing a collection of keys in an entity. Each time a key is
added or removed, the containing entity must be updated. This has potential
performance problems when there are large numbers of entities on the to-Many
side of the relationship, in other words, when there are large numbers of
keys in each secondary key field collection.</p>
<p>If you have a Many-to-Many relationship with a reasonably small number of
entities on one side of the relationship and a large number of entities on
the other side, you can avoid the potential performance problems by defining
the secondary key field on the side with a small number of entities.</p>
<p>For example, in an Employee-to-Organization relationship, the number of
organizations per employee will normally be reasonably small but the number
of employees per organization may be very large. Therefore, to avoid
potential performance problems, the secondary key field should be defined in
the Employee class as shown below.</p>
<pre class="code">
@Entity
class Employee {
@PrimaryKey
long id;
@SecondaryKey(relate=MANY_TO_MANY, relatedEntity=Organization.class)
Set&lt;String&gt; organizations = new HashSet&lt;String&gt;;
String name;
private Employee() {}
}
@Entity
class Organization {
@PrimaryKey
String name;
String description;
}</pre>
<p>If instead a <code>Set&lt;Long&gt; members</code> key had been defined in the
Organization class, this set could potentially have a large number of
elements and performance problems could result.</p>
<h3>Many-to-Many Versus a Relationship Entity</h3>
<p>If you have a Many-to-Many relationship with a large number of entities
on <em>both</em> sides of the relationship, you can avoid the potential
performance problems by using a <em>relationship entity</em>. A
relationship entity defines the relationship between two other entities
using two Many-to-One relationships.</p>
<p>Imagine a relationship between cars and trucks indicating whenever a
particular truck was passed on the road by a particular car. A given car
may pass a large number of trucks and a given truck may be passed by a large
number of cars. First look at a Many-to-Many relationship between these two
entities:</p>
<pre class="code">
@Entity
class Car {
@PrimaryKey
String licenseNumber;
@SecondaryKey(relate=MANY_TO_MANY, relatedEntity=Truck.class)
Set&lt;String&gt; trucksPassed = new HashSet&lt;String&gt;;
String color;
private Car() {}
}
@Entity
class Truck {
@PrimaryKey
String licenseNumber;
int tons;
private Truck() {}
}</pre>
<p>With the Many-to-Many approach above, the <code>trucksPassed</code> set could
potentially have a large number of elements and performance problems could
result.</p>
<p>To apply the relationship entity approach we define a new entity class
named CarPassedTruck representing a single truck passed by a single car. We
remove the secondary key from the Car class and use two secondary keys in
the CarPassedTruck class instead.</p>
<pre class="code">
@Entity
class Car {
@PrimaryKey
String licenseNumber;
String color;
private Car() {}
}
@Entity
class Truck {
@PrimaryKey
String licenseNumber;
int tons;
private Truck() {}
}
@Entity
class CarPassedTruck {
@PrimaryKey
long id;
@SecondaryKey(relate=MANY_TO_ONE, relatedEntity=Car.class)
String carLicense;
@SecondaryKey(relate=MANY_TO_ONE, relatedEntity=Truck.class)
String truckLicense;
private CarPassedTruck() {}
}</pre>
<p>The CarPassedTruck entity can be used to access the relationship by car
license or by truck license.</p>
<p>You may use the relationship entity approach because of the potential
performance problems mentioned above. Or, you may choose to use this
approach in order to store other information about the relationship. For
example, if for each car that passes a truck you wish to record how much
faster the car was going than the truck, then a relationship entity is the
logical place to store that property. In the example below the
speedDifference property is added to the CarPassedTruck class.</p>
<pre class="code">
@Entity
class CarPassedTruck {
@PrimaryKey
long id;
@SecondaryKey(relate=MANY_TO_ONE, relatedEntity=Car.class)
String carLicense;
@SecondaryKey(relate=MANY_TO_ONE, relatedEntity=Truck.class)
String truckLicense;
int speedDifference;
private CarPassedTruck() {}
}</pre>
<p>Be aware that the relationship entity approach adds overhead compared to
Many-to-Many. There is one additional entity and one additional secondary
key. These factors should be weighed against its advantages and the
relevant application access patterns should be considered.</p></div>
<dl>
<dt><span class="simpleTagLabel">Author:</span></dt>
<dd>Mark Hayes</dd>
</dl>
</li>
</ul>
</div>
<div class="summary">
<ul class="blockList">
<li class="blockList">
<!-- ======== CONSTRUCTOR SUMMARY ======== -->
<ul class="blockList">
<li class="blockList"><a name="constructor.summary">
<!-- -->
</a>
<h3>Constructor Summary</h3>
<table class="memberSummary" border="0" cellpadding="3" cellspacing="0" summary="Constructor Summary table, listing constructors, and an explanation">
<caption><span>Constructors</span><span class="tabEnd">&nbsp;</span></caption>
<tr>
<th class="colOne" scope="col">Constructor and Description</th>
</tr>
<tr class="altColor">
<td class="colOne"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#SecondaryIndex-com.sleepycat.je.SecondaryDatabase-com.sleepycat.je.Database-com.sleepycat.persist.PrimaryIndex-java.lang.Class-com.sleepycat.bind.EntryBinding-">SecondaryIndex</a></span>(<a href="../../../com/sleepycat/je/SecondaryDatabase.html" title="class in com.sleepycat.je">SecondaryDatabase</a>&nbsp;database,
<a href="../../../com/sleepycat/je/Database.html" title="class in com.sleepycat.je">Database</a>&nbsp;keysDatabase,
<a href="../../../com/sleepycat/persist/PrimaryIndex.html" title="class in com.sleepycat.persist">PrimaryIndex</a>&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">PK</a>,<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">E</a>&gt;&nbsp;primaryIndex,
java.lang.Class&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>&gt;&nbsp;secondaryKeyClass,
<a href="../../../com/sleepycat/bind/EntryBinding.html" title="interface in com.sleepycat.bind">EntryBinding</a>&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>&gt;&nbsp;secondaryKeyBinding)</code>
<div class="block">Creates a secondary index without using an <code>EntityStore</code>.</div>
</td>
</tr>
</table>
</li>
</ul>
<!-- ========== METHOD SUMMARY =========== -->
<ul class="blockList">
<li class="blockList"><a name="method.summary">
<!-- -->
</a>
<h3>Method Summary</h3>
<table class="memberSummary" border="0" cellpadding="3" cellspacing="0" summary="Method Summary table, listing methods, and an explanation">
<caption><span id="t0" class="activeTableTab"><span>All Methods</span><span class="tabEnd">&nbsp;</span></span><span id="t2" class="tableTab"><span><a href="javascript:show(2);">Instance Methods</a></span><span class="tabEnd">&nbsp;</span></span><span id="t4" class="tableTab"><span><a href="javascript:show(8);">Concrete Methods</a></span><span class="tabEnd">&nbsp;</span></span></caption>
<tr>
<th class="colFirst" scope="col">Modifier and Type</th>
<th class="colLast" scope="col">Method and Description</th>
</tr>
<tr id="i0" class="altColor">
<td class="colFirst"><code>boolean</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#contains-K-">contains</a></span>(K&nbsp;key)</code>
<div class="block">Checks for existence of a key in this index.</div>
</td>
</tr>
<tr id="i1" class="rowColor">
<td class="colFirst"><code>boolean</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#contains-com.sleepycat.je.Transaction-K-com.sleepycat.je.LockMode-">contains</a></span>(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
K&nbsp;key,
<a href="../../../com/sleepycat/je/LockMode.html" title="enum in com.sleepycat.je">LockMode</a>&nbsp;lockMode)</code>
<div class="block">Checks for existence of a key in this index.</div>
</td>
</tr>
<tr id="i2" class="altColor">
<td class="colFirst"><code>long</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#count--">count</a></span>()</code>
<div class="block">Returns a non-transactional count of the entities in this index.</div>
</td>
</tr>
<tr id="i3" class="rowColor">
<td class="colFirst"><code>long</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#count-long-">count</a></span>(long&nbsp;memoryLimit)</code>
<div class="block">Returns a non-transactional count of the entities in this index.</div>
</td>
</tr>
<tr id="i4" class="altColor">
<td class="colFirst"><code>boolean</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#delete-K-">delete</a></span>(K&nbsp;key)</code>
<div class="block">Deletes all entities with a given index key.</div>
</td>
</tr>
<tr id="i5" class="rowColor">
<td class="colFirst"><code>boolean</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#delete-com.sleepycat.je.Transaction-K-">delete</a></span>(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
K&nbsp;key)</code>
<div class="block">Deletes all entities with a given index key.</div>
</td>
</tr>
<tr id="i6" class="altColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/je/OperationResult.html" title="class in com.sleepycat.je">OperationResult</a></code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#delete-com.sleepycat.je.Transaction-K-com.sleepycat.je.WriteOptions-">delete</a></span>(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
K&nbsp;key,
<a href="../../../com/sleepycat/je/WriteOptions.html" title="class in com.sleepycat.je">WriteOptions</a>&nbsp;options)</code>
<div class="block">Deletes all entities with a given index key, using a WriteOptions
parameter and returning an OperationResult.</div>
</td>
</tr>
<tr id="i7" class="rowColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/persist/EntityCursor.html" title="interface in com.sleepycat.persist">EntityCursor</a>&lt;E&gt;</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#entities--">entities</a></span>()</code>
<div class="block">Opens a cursor for traversing all entities in this index.</div>
</td>
</tr>
<tr id="i8" class="altColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/persist/EntityCursor.html" title="interface in com.sleepycat.persist">EntityCursor</a>&lt;E&gt;</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#entities-K-boolean-K-boolean-">entities</a></span>(K&nbsp;fromKey,
boolean&nbsp;fromInclusive,
K&nbsp;toKey,
boolean&nbsp;toInclusive)</code>
<div class="block">Opens a cursor for traversing entities in a key range.</div>
</td>
</tr>
<tr id="i9" class="rowColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/persist/EntityCursor.html" title="interface in com.sleepycat.persist">EntityCursor</a>&lt;E&gt;</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#entities-com.sleepycat.je.Transaction-com.sleepycat.je.CursorConfig-">entities</a></span>(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
<a href="../../../com/sleepycat/je/CursorConfig.html" title="class in com.sleepycat.je">CursorConfig</a>&nbsp;config)</code>
<div class="block">Opens a cursor for traversing all entities in this index.</div>
</td>
</tr>
<tr id="i10" class="altColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/persist/EntityCursor.html" title="interface in com.sleepycat.persist">EntityCursor</a>&lt;E&gt;</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#entities-com.sleepycat.je.Transaction-K-boolean-K-boolean-com.sleepycat.je.CursorConfig-">entities</a></span>(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
K&nbsp;fromKey,
boolean&nbsp;fromInclusive,
K&nbsp;toKey,
boolean&nbsp;toInclusive,
<a href="../../../com/sleepycat/je/CursorConfig.html" title="class in com.sleepycat.je">CursorConfig</a>&nbsp;config)</code>
<div class="block">Opens a cursor for traversing entities in a key range.</div>
</td>
</tr>
<tr id="i11" class="rowColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">E</a></code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#get-SK-">get</a></span>(<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>&nbsp;key)</code>
<div class="block">Gets an entity via a key of this index.</div>
</td>
</tr>
<tr id="i12" class="altColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/persist/EntityResult.html" title="class in com.sleepycat.persist">EntityResult</a>&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">E</a>&gt;</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#get-com.sleepycat.je.Transaction-SK-com.sleepycat.je.Get-com.sleepycat.je.ReadOptions-">get</a></span>(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>&nbsp;key,
<a href="../../../com/sleepycat/je/Get.html" title="enum in com.sleepycat.je">Get</a>&nbsp;getType,
<a href="../../../com/sleepycat/je/ReadOptions.html" title="class in com.sleepycat.je">ReadOptions</a>&nbsp;options)</code>
<div class="block">Gets an entity via a key of this index, using Get type and ReadOptions
parameters, and returning an EntityResult.</div>
</td>
</tr>
<tr id="i13" class="rowColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">E</a></code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#get-com.sleepycat.je.Transaction-SK-com.sleepycat.je.LockMode-">get</a></span>(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>&nbsp;key,
<a href="../../../com/sleepycat/je/LockMode.html" title="enum in com.sleepycat.je">LockMode</a>&nbsp;lockMode)</code>
<div class="block">Gets an entity via a key of this index.</div>
</td>
</tr>
<tr id="i14" class="altColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/je/SecondaryDatabase.html" title="class in com.sleepycat.je">SecondaryDatabase</a></code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#getDatabase--">getDatabase</a></span>()</code>
<div class="block">Returns the underlying secondary database for this index.</div>
</td>
</tr>
<tr id="i15" class="rowColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/bind/EntryBinding.html" title="interface in com.sleepycat.bind">EntryBinding</a>&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>&gt;</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#getKeyBinding--">getKeyBinding</a></span>()</code>
<div class="block">Returns the secondary key binding for the index.</div>
</td>
</tr>
<tr id="i16" class="altColor">
<td class="colFirst"><code>java.lang.Class&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>&gt;</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#getKeyClass--">getKeyClass</a></span>()</code>
<div class="block">Returns the secondary key class for this index.</div>
</td>
</tr>
<tr id="i17" class="rowColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/je/Database.html" title="class in com.sleepycat.je">Database</a></code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#getKeysDatabase--">getKeysDatabase</a></span>()</code>
<div class="block">Returns the underlying secondary database that is not associated with
the primary database and is used for the <a href="../../../com/sleepycat/persist/SecondaryIndex.html#keysIndex"><code>keysIndex</code></a>.</div>
</td>
</tr>
<tr id="i18" class="altColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/persist/PrimaryIndex.html" title="class in com.sleepycat.persist">PrimaryIndex</a>&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">PK</a>,<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">E</a>&gt;</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#getPrimaryIndex--">getPrimaryIndex</a></span>()</code>
<div class="block">Returns the primary index associated with this secondary index.</div>
</td>
</tr>
<tr id="i19" class="rowColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/persist/EntityCursor.html" title="interface in com.sleepycat.persist">EntityCursor</a>&lt;K&gt;</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#keys--">keys</a></span>()</code>
<div class="block">Opens a cursor for traversing all keys in this index.</div>
</td>
</tr>
<tr id="i20" class="altColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/persist/EntityCursor.html" title="interface in com.sleepycat.persist">EntityCursor</a>&lt;K&gt;</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#keys-K-boolean-K-boolean-">keys</a></span>(K&nbsp;fromKey,
boolean&nbsp;fromInclusive,
K&nbsp;toKey,
boolean&nbsp;toInclusive)</code>
<div class="block">Opens a cursor for traversing keys in a key range.</div>
</td>
</tr>
<tr id="i21" class="rowColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/persist/EntityCursor.html" title="interface in com.sleepycat.persist">EntityCursor</a>&lt;K&gt;</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#keys-com.sleepycat.je.Transaction-com.sleepycat.je.CursorConfig-">keys</a></span>(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
<a href="../../../com/sleepycat/je/CursorConfig.html" title="class in com.sleepycat.je">CursorConfig</a>&nbsp;config)</code>
<div class="block">Opens a cursor for traversing all keys in this index.</div>
</td>
</tr>
<tr id="i22" class="altColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/persist/EntityCursor.html" title="interface in com.sleepycat.persist">EntityCursor</a>&lt;K&gt;</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#keys-com.sleepycat.je.Transaction-K-boolean-K-boolean-com.sleepycat.je.CursorConfig-">keys</a></span>(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
K&nbsp;fromKey,
boolean&nbsp;fromInclusive,
K&nbsp;toKey,
boolean&nbsp;toInclusive,
<a href="../../../com/sleepycat/je/CursorConfig.html" title="class in com.sleepycat.je">CursorConfig</a>&nbsp;config)</code>
<div class="block">Opens a cursor for traversing keys in a key range.</div>
</td>
</tr>
<tr id="i23" class="rowColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>,<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">PK</a>&gt;</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#keysIndex--">keysIndex</a></span>()</code>
<div class="block">Returns a read-only keys index that maps secondary key to primary key.</div>
</td>
</tr>
<tr id="i24" class="altColor">
<td class="colFirst"><code>java.util.Map&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>,<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">E</a>&gt;</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#map--">map</a></span>()</code>
<div class="block">Returns a standard Java map based on this entity index.</div>
</td>
</tr>
<tr id="i25" class="rowColor">
<td class="colFirst"><code>java.util.SortedMap&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>,<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">E</a>&gt;</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#sortedMap--">sortedMap</a></span>()</code>
<div class="block">Returns a standard Java sorted map based on this entity index.</div>
</td>
</tr>
<tr id="i26" class="altColor">
<td class="colFirst"><code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">PK</a>,<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">E</a>&gt;</code></td>
<td class="colLast"><code><span class="memberNameLink"><a href="../../../com/sleepycat/persist/SecondaryIndex.html#subIndex-SK-">subIndex</a></span>(<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>&nbsp;key)</code>
<div class="block">Returns an index that maps primary key to entity for the subset of
entities having a given secondary key (duplicates).</div>
</td>
</tr>
</table>
<ul class="blockList">
<li class="blockList"><a name="methods.inherited.from.class.java.lang.Object">
<!-- -->
</a>
<h3>Methods inherited from class&nbsp;java.lang.Object</h3>
<code>clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait</code></li>
</ul>
</li>
</ul>
</li>
</ul>
</div>
<div class="details">
<ul class="blockList">
<li class="blockList">
<!-- ========= CONSTRUCTOR DETAIL ======== -->
<ul class="blockList">
<li class="blockList"><a name="constructor.detail">
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</a>
<h3>Constructor Detail</h3>
<a name="SecondaryIndex-com.sleepycat.je.SecondaryDatabase-com.sleepycat.je.Database-com.sleepycat.persist.PrimaryIndex-java.lang.Class-com.sleepycat.bind.EntryBinding-">
<!-- -->
</a>
<ul class="blockListLast">
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<h4>SecondaryIndex</h4>
<pre>public&nbsp;SecondaryIndex(<a href="../../../com/sleepycat/je/SecondaryDatabase.html" title="class in com.sleepycat.je">SecondaryDatabase</a>&nbsp;database,
<a href="../../../com/sleepycat/je/Database.html" title="class in com.sleepycat.je">Database</a>&nbsp;keysDatabase,
<a href="../../../com/sleepycat/persist/PrimaryIndex.html" title="class in com.sleepycat.persist">PrimaryIndex</a>&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">PK</a>,<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">E</a>&gt;&nbsp;primaryIndex,
java.lang.Class&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>&gt;&nbsp;secondaryKeyClass,
<a href="../../../com/sleepycat/bind/EntryBinding.html" title="interface in com.sleepycat.bind">EntryBinding</a>&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>&gt;&nbsp;secondaryKeyBinding)
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block">Creates a secondary index without using an <code>EntityStore</code>.
When using an <a href="../../../com/sleepycat/persist/EntityStore.html" title="class in com.sleepycat.persist"><code>EntityStore</code></a>, call <a href="../../../com/sleepycat/persist/EntityStore.html#getSecondaryIndex-com.sleepycat.persist.PrimaryIndex-java.lang.Class-java.lang.String-"><code>getSecondaryIndex</code></a> instead.
<p>This constructor is not normally needed and is provided for
applications that wish to use custom bindings along with the Direct
Persistence Layer. Normally, <a href="../../../com/sleepycat/persist/EntityStore.html#getSecondaryIndex-com.sleepycat.persist.PrimaryIndex-java.lang.Class-java.lang.String-"><code>getSecondaryIndex</code></a> is used instead.</p></div>
<dl>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>database</code> - the secondary database used for all access other than
via a <a href="../../../com/sleepycat/persist/SecondaryIndex.html#keysIndex"><code>keysIndex</code></a>.</dd>
<dd><code>keysDatabase</code> - another handle on the secondary database, opened
without association to the primary, and used only for access via a
<a href="../../../com/sleepycat/persist/SecondaryIndex.html#keysIndex"><code>keysIndex</code></a>. If this argument is null and the <a href="../../../com/sleepycat/persist/SecondaryIndex.html#keysIndex"><code>keysIndex</code></a>
method is called, then the keys database will be opened automatically;
however, the user is then responsible for closing the keys database. To
get the keys database in order to close it, call <a href="../../../com/sleepycat/persist/SecondaryIndex.html#getKeysDatabase--"><code>getKeysDatabase()</code></a>.</dd>
<dd><code>primaryIndex</code> - the primary index associated with this secondary
index.</dd>
<dd><code>secondaryKeyClass</code> - the class of the secondary key.</dd>
<dd><code>secondaryKeyBinding</code> - the binding to be used for secondary keys.</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
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</ul>
</li>
</ul>
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<h3>Method Detail</h3>
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<h4>getDatabase</h4>
<pre>public&nbsp;<a href="../../../com/sleepycat/je/SecondaryDatabase.html" title="class in com.sleepycat.je">SecondaryDatabase</a>&nbsp;getDatabase()</pre>
<div class="block">Returns the underlying secondary database for this index.</div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../com/sleepycat/persist/EntityIndex.html#getDatabase--">getDatabase</a></code>&nbsp;in interface&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>,<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">E</a>&gt;</code></dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the secondary database.</dd>
</dl>
</li>
</ul>
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<pre>public&nbsp;<a href="../../../com/sleepycat/je/Database.html" title="class in com.sleepycat.je">Database</a>&nbsp;getKeysDatabase()</pre>
<div class="block">Returns the underlying secondary database that is not associated with
the primary database and is used for the <a href="../../../com/sleepycat/persist/SecondaryIndex.html#keysIndex"><code>keysIndex</code></a>.</div>
<dl>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the keys database.</dd>
</dl>
</li>
</ul>
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<h4>getPrimaryIndex</h4>
<pre>public&nbsp;<a href="../../../com/sleepycat/persist/PrimaryIndex.html" title="class in com.sleepycat.persist">PrimaryIndex</a>&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">PK</a>,<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">E</a>&gt;&nbsp;getPrimaryIndex()</pre>
<div class="block">Returns the primary index associated with this secondary index.</div>
<dl>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the primary index.</dd>
</dl>
</li>
</ul>
<a name="getKeyClass--">
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<h4>getKeyClass</h4>
<pre>public&nbsp;java.lang.Class&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>&gt;&nbsp;getKeyClass()</pre>
<div class="block">Returns the secondary key class for this index.</div>
<dl>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the class.</dd>
</dl>
</li>
</ul>
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<pre>public&nbsp;<a href="../../../com/sleepycat/bind/EntryBinding.html" title="interface in com.sleepycat.bind">EntryBinding</a>&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>&gt;&nbsp;getKeyBinding()</pre>
<div class="block">Returns the secondary key binding for the index.</div>
<dl>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the key binding.</dd>
</dl>
</li>
</ul>
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<h4>keysIndex</h4>
<pre>public&nbsp;<a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>,<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">PK</a>&gt;&nbsp;keysIndex()
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block">Returns a read-only keys index that maps secondary key to primary key.
When accessing the keys index, the primary key is returned rather than
the entity. When only the primary key is needed and not the entire
entity, using the keys index is less expensive than using the secondary
index because the primary index does not have to be accessed.
<p>Note the following in the unusual case that you are <em>not</em>
using an <code>EntityStore</code>: This method will open the keys
database, a second database handle for the secondary database, if it is
not already open. In this case, if you are <em>not</em> using an
<code>EntityStore</code>, then you are responsible for closing the
database returned by <a href="../../../com/sleepycat/persist/SecondaryIndex.html#getKeysDatabase--"><code>getKeysDatabase()</code></a> before closing the
environment. If you <em>are</em> using an <code>EntityStore</code>, the
keys database will be closed automatically by <a href="../../../com/sleepycat/persist/EntityStore.html#close--"><code>EntityStore.close()</code></a>.</p></div>
<dl>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the keys index.</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
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</a><a name="subIndex-SK-">
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<h4>subIndex</h4>
<pre>public&nbsp;<a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">PK</a>,<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">E</a>&gt;&nbsp;subIndex(<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>&nbsp;key)
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block">Returns an index that maps primary key to entity for the subset of
entities having a given secondary key (duplicates). A sub-index is
convenient when you are interested in working with the subset of
entities having a particular secondary key value.
<p>When using a <a href="../../../com/sleepycat/persist/model/Relationship.html#MANY_TO_ONE"><code>MANY_TO_ONE</code></a> or <a href="../../../com/sleepycat/persist/model/Relationship.html#MANY_TO_MANY"><code>MANY_TO_MANY</code></a> secondary key, the sub-index
represents the left (MANY) side of a relationship.</p></div>
<dl>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>key</code> - the secondary key that identifies the entities in the
sub-index.</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the sub-index.</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
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<h4>get</h4>
<pre>public&nbsp;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">E</a>&nbsp;get(<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>&nbsp;key)
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#get-K-">EntityIndex</a></code></span></div>
<div class="block">Gets an entity via a key of this index.
<p>The operation will not be transaction protected, and <a href="../../../com/sleepycat/je/LockMode.html#DEFAULT"><code>LockMode.DEFAULT</code></a> is used implicitly.</p></div>
<dl>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>key</code> - the key to search for.</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the value mapped to the given key, or null if the key is not
present in the index.
<!-- begin JE only --></dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/OperationFailureException.html" title="class in com.sleepycat.je">OperationFailureException</a></code> - if one of the <a
href="../je/OperationFailureException.html#readFailures">Read Operation
Failures</a> occurs.</dd>
<dd><code><a href="../../../com/sleepycat/je/EnvironmentFailureException.html" title="class in com.sleepycat.je">EnvironmentFailureException</a></code> - if an unexpected, internal or
environment-wide failure occurs.
<!-- end JE only --></dd>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
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<pre>public&nbsp;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">E</a>&nbsp;get(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>&nbsp;key,
<a href="../../../com/sleepycat/je/LockMode.html" title="enum in com.sleepycat.je">LockMode</a>&nbsp;lockMode)
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#get-com.sleepycat.je.Transaction-K-com.sleepycat.je.LockMode-">EntityIndex</a></code></span></div>
<div class="block">Gets an entity via a key of this index.</div>
<dl>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>txn</code> - the transaction used to protect this operation, or null
if the operation should not be transaction protected.</dd>
<dd><code>key</code> - the key to search for.</dd>
<dd><code>lockMode</code> - the lock mode to use for this operation, or null to
use <a href="../../../com/sleepycat/je/LockMode.html#DEFAULT"><code>LockMode.DEFAULT</code></a>.</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the value mapped to the given key, or null if the key is not
present in the index.
<!-- begin JE only --></dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/OperationFailureException.html" title="class in com.sleepycat.je">OperationFailureException</a></code> - if one of the <a
href="../je/OperationFailureException.html#readFailures">Read Operation
Failures</a> occurs.</dd>
<dd><code><a href="../../../com/sleepycat/je/EnvironmentFailureException.html" title="class in com.sleepycat.je">EnvironmentFailureException</a></code> - if an unexpected, internal or
environment-wide failure occurs.
<!-- end JE only --></dd>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
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<h4>get</h4>
<pre>public&nbsp;<a href="../../../com/sleepycat/persist/EntityResult.html" title="class in com.sleepycat.persist">EntityResult</a>&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">E</a>&gt;&nbsp;get(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>&nbsp;key,
<a href="../../../com/sleepycat/je/Get.html" title="enum in com.sleepycat.je">Get</a>&nbsp;getType,
<a href="../../../com/sleepycat/je/ReadOptions.html" title="class in com.sleepycat.je">ReadOptions</a>&nbsp;options)
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#get-com.sleepycat.je.Transaction-K-com.sleepycat.je.Get-com.sleepycat.je.ReadOptions-">EntityIndex</a></code></span></div>
<div class="block">Gets an entity via a key of this index, using Get type and ReadOptions
parameters, and returning an EntityResult.</div>
<dl>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>txn</code> - the transaction used to protect this operation, or null
if the operation should not be transaction protected.</dd>
<dd><code>key</code> - the key to search for.</dd>
<dd><code>getType</code> - must be <a href="../../../com/sleepycat/je/Get.html#SEARCH"><code>Get.SEARCH</code></a>.</dd>
<dd><code>options</code> - the ReadOptions, or null to use default options.</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the EntityResult, including the value mapped to the given key,
or null if the key is not present in the index.</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/OperationFailureException.html" title="class in com.sleepycat.je">OperationFailureException</a></code> - if one of the <a
href="../je/OperationFailureException.html#readFailures">Read Operation
Failures</a> occurs.</dd>
<dd><code><a href="../../../com/sleepycat/je/EnvironmentFailureException.html" title="class in com.sleepycat.je">EnvironmentFailureException</a></code> - if an unexpected, internal or
environment-wide failure occurs.</dd>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
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<h4>map</h4>
<pre>public&nbsp;java.util.Map&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>,<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">E</a>&gt;&nbsp;map()</pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#map--">EntityIndex</a></code></span></div>
<div class="block">Returns a standard Java map based on this entity index. The <a href="../../../com/sleepycat/collections/StoredMap.html" title="class in com.sleepycat.collections"><code>StoredMap</code></a> returned is defined by the <a href="../../../com/sleepycat/collections/package-summary.html">Collections API</a>. Stored collections conform
to the standard Java collections framework interface.</div>
<dl>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the map.</dd>
</dl>
</li>
</ul>
<a name="sortedMap--">
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<h4>sortedMap</h4>
<pre>public&nbsp;java.util.SortedMap&lt;<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">SK</a>,<a href="../../../com/sleepycat/persist/SecondaryIndex.html" title="type parameter in SecondaryIndex">E</a>&gt;&nbsp;sortedMap()</pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#sortedMap--">EntityIndex</a></code></span></div>
<div class="block">Returns a standard Java sorted map based on this entity index. The
<a href="../../../com/sleepycat/collections/StoredSortedMap.html" title="class in com.sleepycat.collections"><code>StoredSortedMap</code></a> returned is defined by the <a href="../../../com/sleepycat/collections/package-summary.html">Collections API</a>. Stored collections conform
to the standard Java collections framework interface.</div>
<dl>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the map.</dd>
</dl>
</li>
</ul>
<a name="contains-java.lang.Object-">
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<h4>contains</h4>
<pre>public&nbsp;boolean&nbsp;contains(K&nbsp;key)
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#contains-K-">EntityIndex</a></code></span></div>
<div class="block">Checks for existence of a key in this index.
<p>The operation will not be transaction protected, and <a href="../../../com/sleepycat/je/LockMode.html#DEFAULT"><code>LockMode.DEFAULT</code></a> is used implicitly.</p>
<!-- begin JE only -->
<p><code>READ_UNCOMMITTED</code> can be used with this method to reduce I/O,
since the record data item will not be read. This is the same benefit
as described in <a href="#keyCursorReadUncommitted">Key Cursor
Optimization with READ_UNCOMMITTED</a></p>
<!-- end JE only --></div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../com/sleepycat/persist/EntityIndex.html#contains-K-">contains</a></code>&nbsp;in interface&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;K,E&gt;</code></dd>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>key</code> - the key to search for.</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>whether the key exists in the index.
<!-- begin JE only --></dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/OperationFailureException.html" title="class in com.sleepycat.je">OperationFailureException</a></code> - if one of the <a
href="../je/OperationFailureException.html#readFailures">Read Operation
Failures</a> occurs.</dd>
<dd><code><a href="../../../com/sleepycat/je/EnvironmentFailureException.html" title="class in com.sleepycat.je">EnvironmentFailureException</a></code> - if an unexpected, internal or
environment-wide failure occurs.
<!-- end JE only --></dd>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
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<h4>contains</h4>
<pre>public&nbsp;boolean&nbsp;contains(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
K&nbsp;key,
<a href="../../../com/sleepycat/je/LockMode.html" title="enum in com.sleepycat.je">LockMode</a>&nbsp;lockMode)
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#contains-com.sleepycat.je.Transaction-K-com.sleepycat.je.LockMode-">EntityIndex</a></code></span></div>
<div class="block">Checks for existence of a key in this index.
<!-- begin JE only -->
<p><code>READ_UNCOMMITTED</code> can be used with this method to reduce I/O,
since the record data item will not be read. This is the same benefit
as described in <a href="#keyCursorReadUncommitted">Key Cursor
Optimization with READ_UNCOMMITTED</a></p>
<!-- end JE only --></div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../com/sleepycat/persist/EntityIndex.html#contains-com.sleepycat.je.Transaction-K-com.sleepycat.je.LockMode-">contains</a></code>&nbsp;in interface&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;K,E&gt;</code></dd>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>txn</code> - the transaction used to protect this operation, or null
if the operation should not be transaction protected.</dd>
<dd><code>key</code> - the key to search for.</dd>
<dd><code>lockMode</code> - the lock mode to use for this operation, or null to
use <a href="../../../com/sleepycat/je/LockMode.html#DEFAULT"><code>LockMode.DEFAULT</code></a>.</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>whether the key exists in the index.
<!-- begin JE only --></dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/OperationFailureException.html" title="class in com.sleepycat.je">OperationFailureException</a></code> - if one of the <a
href="../je/OperationFailureException.html#readFailures">Read Operation
Failures</a> occurs.</dd>
<dd><code><a href="../../../com/sleepycat/je/EnvironmentFailureException.html" title="class in com.sleepycat.je">EnvironmentFailureException</a></code> - if an unexpected, internal or
environment-wide failure occurs.
<!-- end JE only --></dd>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
<a name="count--">
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</a>
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<li class="blockList">
<h4>count</h4>
<pre>public&nbsp;long&nbsp;count()
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#count--">EntityIndex</a></code></span></div>
<div class="block">Returns a non-transactional count of the entities in this index.
<!-- begin JE only -->
<p>This operation is faster than obtaining a count by scanning the index
manually, and will not perturb the current contents of the cache.
However, the count is not guaranteed to be accurate if there are
concurrent updates. Note that this method does scan a significant
portion of the index and should be considered a fairly expensive
operation.</p>
<p>This operation will disable deletion of log files by the JE log
cleaner during its execution and will consume a certain amount of
memory (but without affecting the memory that is available for the
JE cache). To avoid excessive memory consumption (and a potential
<code>OutOfMemoryError</code>) this method places an internal limit on
its memory consumption. If this limit is reached, the method will
still work properly, but its performance will degrade. To specify
a different memory limit than the one used by this method, use the
<a href="../../../com/sleepycat/persist/EntityIndex.html#count-long-"><code>EntityIndex.count(long memoryLimit)</code></a> method.</p>
<!-- end JE only --></div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../com/sleepycat/persist/EntityIndex.html#count--">count</a></code>&nbsp;in interface&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;K,E&gt;</code></dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the number of entities in this index.
<!-- begin JE only --></dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/OperationFailureException.html" title="class in com.sleepycat.je">OperationFailureException</a></code> - if one of the <a
href="../je/OperationFailureException.html#readFailures">Read Operation
Failures</a> occurs.</dd>
<dd><code><a href="../../../com/sleepycat/je/EnvironmentFailureException.html" title="class in com.sleepycat.je">EnvironmentFailureException</a></code> - if an unexpected, internal or
environment-wide failure occurs.
<!-- end JE only --></dd>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
<a name="count-long-">
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</a>
<ul class="blockList">
<li class="blockList">
<h4>count</h4>
<pre>public&nbsp;long&nbsp;count(long&nbsp;memoryLimit)
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#count-long-">EntityIndex</a></code></span></div>
<div class="block">Returns a non-transactional count of the entities in this index.
<p>This operation is faster than obtaining a count by scanning the index
manually, and will not perturb the current contents of the cache.
However, the count is not guaranteed to be accurate if there are
concurrent updates. Note that this method does scan a significant
portion of the index and should be considered a fairly expensive
operation.</p>
<p>This operation will disable deletion of log files by the JE log
cleaner during its execution and will consume a certain amount of
memory (but without affecting the memory that is available for the
JE cache). To avoid excessive memory consumption (and a potential
<code>OutOfMemoryError</code>) this method takes as input an upper bound
on the memory it may consume. If this limit is reached, the method
will still work properly, but its performance will degrade.</p></div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../com/sleepycat/persist/EntityIndex.html#count-long-">count</a></code>&nbsp;in interface&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;K,E&gt;</code></dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the number of entities in this index.</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/OperationFailureException.html" title="class in com.sleepycat.je">OperationFailureException</a></code> - if one of the <a
href="../je/OperationFailureException.html#readFailures">Read Operation
Failures</a> occurs.</dd>
<dd><code><a href="../../../com/sleepycat/je/EnvironmentFailureException.html" title="class in com.sleepycat.je">EnvironmentFailureException</a></code> - if an unexpected, internal or
environment-wide failure occurs.</dd>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
<a name="delete-java.lang.Object-">
<!-- -->
</a><a name="delete-K-">
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</a>
<ul class="blockList">
<li class="blockList">
<h4>delete</h4>
<pre>public&nbsp;boolean&nbsp;delete(K&nbsp;key)
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#delete-K-">EntityIndex</a></code></span></div>
<div class="block">Deletes all entities with a given index key.
<p>Auto-commit is used implicitly if the store is transactional.</p></div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../com/sleepycat/persist/EntityIndex.html#delete-K-">delete</a></code>&nbsp;in interface&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;K,E&gt;</code></dd>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>key</code> - the key to search for.</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>whether any entities were deleted.
<!-- begin JE only --></dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/OperationFailureException.html" title="class in com.sleepycat.je">OperationFailureException</a></code> - if one of the <a
href="../je/OperationFailureException.html#writeFailures">Write
Operation Failures</a> occurs.</dd>
<dd><code><a href="../../../com/sleepycat/je/EnvironmentFailureException.html" title="class in com.sleepycat.je">EnvironmentFailureException</a></code> - if an unexpected, internal or
environment-wide failure occurs.
<!-- end JE only --></dd>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
<a name="delete-com.sleepycat.je.Transaction-java.lang.Object-">
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</a><a name="delete-com.sleepycat.je.Transaction-K-">
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</a>
<ul class="blockList">
<li class="blockList">
<h4>delete</h4>
<pre>public&nbsp;boolean&nbsp;delete(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
K&nbsp;key)
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#delete-com.sleepycat.je.Transaction-K-">EntityIndex</a></code></span></div>
<div class="block">Deletes all entities with a given index key.</div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../com/sleepycat/persist/EntityIndex.html#delete-com.sleepycat.je.Transaction-K-">delete</a></code>&nbsp;in interface&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;K,E&gt;</code></dd>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>txn</code> - the transaction used to protect this operation, null to use
auto-commit, or null if the store is non-transactional.</dd>
<dd><code>key</code> - the key to search for.</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>whether any entities were deleted.
<!-- begin JE only --></dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/OperationFailureException.html" title="class in com.sleepycat.je">OperationFailureException</a></code> - if one of the <a
href="../je/OperationFailureException.html#writeFailures">Write
Operation Failures</a> occurs.</dd>
<dd><code><a href="../../../com/sleepycat/je/EnvironmentFailureException.html" title="class in com.sleepycat.je">EnvironmentFailureException</a></code> - if an unexpected, internal or
environment-wide failure occurs.
<!-- end JE only --></dd>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
<a name="delete-com.sleepycat.je.Transaction-java.lang.Object-com.sleepycat.je.WriteOptions-">
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</a><a name="delete-com.sleepycat.je.Transaction-K-com.sleepycat.je.WriteOptions-">
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<h4>delete</h4>
<pre>public&nbsp;<a href="../../../com/sleepycat/je/OperationResult.html" title="class in com.sleepycat.je">OperationResult</a>&nbsp;delete(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
K&nbsp;key,
<a href="../../../com/sleepycat/je/WriteOptions.html" title="class in com.sleepycat.je">WriteOptions</a>&nbsp;options)
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#delete-com.sleepycat.je.Transaction-K-com.sleepycat.je.WriteOptions-">EntityIndex</a></code></span></div>
<div class="block">Deletes all entities with a given index key, using a WriteOptions
parameter and returning an OperationResult.</div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../com/sleepycat/persist/EntityIndex.html#delete-com.sleepycat.je.Transaction-K-com.sleepycat.je.WriteOptions-">delete</a></code>&nbsp;in interface&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;K,E&gt;</code></dd>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>txn</code> - the transaction used to protect this operation, null to use
auto-commit, or null if the store is non-transactional.</dd>
<dd><code>key</code> - the key to search for.</dd>
<dd><code>options</code> - the WriteOptions, or null to use default options.</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the OperationResult if any entities were deleted, else null. If</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/OperationFailureException.html" title="class in com.sleepycat.je">OperationFailureException</a></code> - if one of the <a
href="../je/OperationFailureException.html#writeFailures">Write
Operation Failures</a> occurs.</dd>
<dd><code><a href="../../../com/sleepycat/je/EnvironmentFailureException.html" title="class in com.sleepycat.je">EnvironmentFailureException</a></code> - if an unexpected, internal or
environment-wide failure occurs.</dd>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
<a name="keys--">
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</a>
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<li class="blockList">
<h4>keys</h4>
<pre>public&nbsp;<a href="../../../com/sleepycat/persist/EntityCursor.html" title="interface in com.sleepycat.persist">EntityCursor</a>&lt;K&gt;&nbsp;keys()
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#keys--">EntityIndex</a></code></span></div>
<div class="block">Opens a cursor for traversing all keys in this index.
<p>The operations performed with the cursor will not be transaction
protected, and <a href="../../../com/sleepycat/je/CursorConfig.html#DEFAULT"><code>CursorConfig.DEFAULT</code></a> is used implicitly. If the
store is transactional, the cursor may not be used to update or delete
entities.</p>
<!-- begin JE only -->
<p>Note that <code>READ_UNCOMMITTED</code> can be used with a key cursor to
reduce I/O, potentially providing significant performance benefits. See
<a href="#keyCursorReadUncommitted">Key Cursor Optimization with
READ_UNCOMMITTED</a></p>
<!-- end JE only --></div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../com/sleepycat/persist/EntityIndex.html#keys--">keys</a></code>&nbsp;in interface&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;K,E&gt;</code></dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the cursor.</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
<a name="keys-com.sleepycat.je.Transaction-com.sleepycat.je.CursorConfig-">
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</a>
<ul class="blockList">
<li class="blockList">
<h4>keys</h4>
<pre>public&nbsp;<a href="../../../com/sleepycat/persist/EntityCursor.html" title="interface in com.sleepycat.persist">EntityCursor</a>&lt;K&gt;&nbsp;keys(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
<a href="../../../com/sleepycat/je/CursorConfig.html" title="class in com.sleepycat.je">CursorConfig</a>&nbsp;config)
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#keys-com.sleepycat.je.Transaction-com.sleepycat.je.CursorConfig-">EntityIndex</a></code></span></div>
<div class="block">Opens a cursor for traversing all keys in this index.
<!-- begin JE only -->
<p>Note that <code>READ_UNCOMMITTED</code> can be used with a key cursor to
reduce I/O, potentially providing significant performance benefits. See
<a href="#keyCursorReadUncommitted">Key Cursor Optimization with
READ_UNCOMMITTED</a></p>
<!-- end JE only --></div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../com/sleepycat/persist/EntityIndex.html#keys-com.sleepycat.je.Transaction-com.sleepycat.je.CursorConfig-">keys</a></code>&nbsp;in interface&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;K,E&gt;</code></dd>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>txn</code> - the transaction used to protect all operations performed with
the cursor, or null if the operations should not be transaction
protected. If the store is non-transactional, null must be specified.
For a transactional store the transaction is optional for read-only
access and required for read-write access.</dd>
<dd><code>config</code> - the cursor configuration that determines the default lock
mode used for all cursor operations, or null to implicitly use <a href="../../../com/sleepycat/je/CursorConfig.html#DEFAULT"><code>CursorConfig.DEFAULT</code></a>.</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the cursor.</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
<a name="entities--">
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</a>
<ul class="blockList">
<li class="blockList">
<h4>entities</h4>
<pre>public&nbsp;<a href="../../../com/sleepycat/persist/EntityCursor.html" title="interface in com.sleepycat.persist">EntityCursor</a>&lt;E&gt;&nbsp;entities()
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#entities--">EntityIndex</a></code></span></div>
<div class="block">Opens a cursor for traversing all entities in this index.
<p>The operations performed with the cursor will not be transaction
protected, and <a href="../../../com/sleepycat/je/CursorConfig.html#DEFAULT"><code>CursorConfig.DEFAULT</code></a> is used implicitly. If the
store is transactional, the cursor may not be used to update or delete
entities.</p></div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../com/sleepycat/persist/EntityIndex.html#entities--">entities</a></code>&nbsp;in interface&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;K,E&gt;</code></dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the cursor.</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
<a name="entities-com.sleepycat.je.Transaction-com.sleepycat.je.CursorConfig-">
<!-- -->
</a>
<ul class="blockList">
<li class="blockList">
<h4>entities</h4>
<pre>public&nbsp;<a href="../../../com/sleepycat/persist/EntityCursor.html" title="interface in com.sleepycat.persist">EntityCursor</a>&lt;E&gt;&nbsp;entities(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
<a href="../../../com/sleepycat/je/CursorConfig.html" title="class in com.sleepycat.je">CursorConfig</a>&nbsp;config)
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#entities-com.sleepycat.je.Transaction-com.sleepycat.je.CursorConfig-">EntityIndex</a></code></span></div>
<div class="block">Opens a cursor for traversing all entities in this index.</div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../com/sleepycat/persist/EntityIndex.html#entities-com.sleepycat.je.Transaction-com.sleepycat.je.CursorConfig-">entities</a></code>&nbsp;in interface&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;K,E&gt;</code></dd>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>txn</code> - the transaction used to protect all operations performed with
the cursor, or null if the operations should not be transaction
protected. If the store is non-transactional, null must be specified.
For a transactional store the transaction is optional for read-only
access and required for read-write access.</dd>
<dd><code>config</code> - the cursor configuration that determines the default lock
mode used for all cursor operations, or null to implicitly use <a href="../../../com/sleepycat/je/CursorConfig.html#DEFAULT"><code>CursorConfig.DEFAULT</code></a>.</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the cursor.</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
<a name="keys-java.lang.Object-boolean-java.lang.Object-boolean-">
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</a><a name="keys-K-boolean-K-boolean-">
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</a>
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<h4>keys</h4>
<pre>public&nbsp;<a href="../../../com/sleepycat/persist/EntityCursor.html" title="interface in com.sleepycat.persist">EntityCursor</a>&lt;K&gt;&nbsp;keys(K&nbsp;fromKey,
boolean&nbsp;fromInclusive,
K&nbsp;toKey,
boolean&nbsp;toInclusive)
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#keys-K-boolean-K-boolean-">EntityIndex</a></code></span></div>
<div class="block">Opens a cursor for traversing keys in a key range.
<p>The operations performed with the cursor will not be transaction
protected, and <a href="../../../com/sleepycat/je/CursorConfig.html#DEFAULT"><code>CursorConfig.DEFAULT</code></a> is used implicitly. If the
store is transactional, the cursor may not be used to update or delete
entities.</p>
<!-- begin JE only -->
<p>Note that <code>READ_UNCOMMITTED</code> can be used with a key cursor to
reduce I/O, potentially providing significant performance benefits. See
<a href="#keyCursorReadUncommitted">Key Cursor Optimization with
READ_UNCOMMITTED</a></p>
<!-- end JE only --></div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../com/sleepycat/persist/EntityIndex.html#keys-K-boolean-K-boolean-">keys</a></code>&nbsp;in interface&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;K,E&gt;</code></dd>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>fromKey</code> - is the lower bound of the key range, or null if the range
has no lower bound.</dd>
<dd><code>fromInclusive</code> - is true if keys greater than or equal to fromKey
should be included in the key range, or false if only keys greater than
fromKey should be included.</dd>
<dd><code>toKey</code> - is the upper bound of the key range, or null if the range
has no upper bound.</dd>
<dd><code>toInclusive</code> - is true if keys less than or equal to toKey should be
included in the key range, or false if only keys less than toKey should
be included.</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the cursor.</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
<a name="keys-com.sleepycat.je.Transaction-java.lang.Object-boolean-java.lang.Object-boolean-com.sleepycat.je.CursorConfig-">
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</a><a name="keys-com.sleepycat.je.Transaction-K-boolean-K-boolean-com.sleepycat.je.CursorConfig-">
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</a>
<ul class="blockList">
<li class="blockList">
<h4>keys</h4>
<pre>public&nbsp;<a href="../../../com/sleepycat/persist/EntityCursor.html" title="interface in com.sleepycat.persist">EntityCursor</a>&lt;K&gt;&nbsp;keys(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
K&nbsp;fromKey,
boolean&nbsp;fromInclusive,
K&nbsp;toKey,
boolean&nbsp;toInclusive,
<a href="../../../com/sleepycat/je/CursorConfig.html" title="class in com.sleepycat.je">CursorConfig</a>&nbsp;config)
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#keys-com.sleepycat.je.Transaction-K-boolean-K-boolean-com.sleepycat.je.CursorConfig-">EntityIndex</a></code></span></div>
<div class="block">Opens a cursor for traversing keys in a key range.
<!-- begin JE only -->
<a name="keyCursorReadUncommitted"><h4>Key Cursor Optimization with
READ_UNCOMMITTED</h4></a>
<p>Using a key cursor potentially has a large performance benefit when
the <code>READ_UNCOMMITTED</code> isolation mode is used. In this case, if
the record data is not in the JE cache, it will not be read from disk.
The performance benefit is potentially large because random access disk
reads may be reduced. Examples are:</p>
<ul>
<li>Scanning all records in key order, when the entity is not needed and
<code>READ_UNCOMMITTED</code> isolation is acceptable.</li>
<li>Skipping over records quickly to perform approximate pagination with
<code>READ_UNCOMMITTED</code> isolation.</li>
</ul>
<p>For other isolation modes (<code>READ_COMMITTED</code>, <code>REPEATABLE_READ</code> and <code>SERIALIZABLE</code>), the performance benefit of a
key cursor is not as significant. In this case, the data item must be
read into the JE cache if it is not already present, in order to lock
the record. The only performance benefit is that the data will not be
copied from the JE cache to the application's entry parameter, and will
not be unmarshalled into an entity object.</p>
<p>For information on specifying isolation modes, see <a href="../../../com/sleepycat/je/LockMode.html" title="enum in com.sleepycat.je"><code>LockMode</code></a>,
<a href="../../../com/sleepycat/je/CursorConfig.html" title="class in com.sleepycat.je"><code>CursorConfig</code></a> and <a href="../../../com/sleepycat/je/TransactionConfig.html" title="class in com.sleepycat.je"><code>TransactionConfig</code></a>.</p>
<!-- end JE only --></div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../com/sleepycat/persist/EntityIndex.html#keys-com.sleepycat.je.Transaction-K-boolean-K-boolean-com.sleepycat.je.CursorConfig-">keys</a></code>&nbsp;in interface&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;K,E&gt;</code></dd>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>txn</code> - the transaction used to protect all operations performed with
the cursor, or null if the operations should not be transaction
protected. If the store is non-transactional, null must be specified.
For a transactional store the transaction is optional for read-only
access and required for read-write access.</dd>
<dd><code>fromKey</code> - is the lower bound of the key range, or null if the range
has no lower bound.</dd>
<dd><code>fromInclusive</code> - is true if keys greater than or equal to fromKey
should be included in the key range, or false if only keys greater than
fromKey should be included.</dd>
<dd><code>toKey</code> - is the upper bound of the key range, or null if the range
has no upper bound.</dd>
<dd><code>toInclusive</code> - is true if keys less than or equal to toKey should be
included in the key range, or false if only keys less than toKey should
be included.</dd>
<dd><code>config</code> - the cursor configuration that determines the default lock
mode used for all cursor operations, or null to implicitly use <a href="../../../com/sleepycat/je/CursorConfig.html#DEFAULT"><code>CursorConfig.DEFAULT</code></a>.</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the cursor.</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
<a name="entities-java.lang.Object-boolean-java.lang.Object-boolean-">
<!-- -->
</a><a name="entities-K-boolean-K-boolean-">
<!-- -->
</a>
<ul class="blockList">
<li class="blockList">
<h4>entities</h4>
<pre>public&nbsp;<a href="../../../com/sleepycat/persist/EntityCursor.html" title="interface in com.sleepycat.persist">EntityCursor</a>&lt;E&gt;&nbsp;entities(K&nbsp;fromKey,
boolean&nbsp;fromInclusive,
K&nbsp;toKey,
boolean&nbsp;toInclusive)
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#entities-K-boolean-K-boolean-">EntityIndex</a></code></span></div>
<div class="block">Opens a cursor for traversing entities in a key range.
<p>The operations performed with the cursor will not be transaction
protected, and <a href="../../../com/sleepycat/je/CursorConfig.html#DEFAULT"><code>CursorConfig.DEFAULT</code></a> is used implicitly. If the
store is transactional, the cursor may not be used to update or delete
entities.</p></div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../com/sleepycat/persist/EntityIndex.html#entities-K-boolean-K-boolean-">entities</a></code>&nbsp;in interface&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;K,E&gt;</code></dd>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>fromKey</code> - is the lower bound of the key range, or null if the range
has no lower bound.</dd>
<dd><code>fromInclusive</code> - is true if keys greater than or equal to fromKey
should be included in the key range, or false if only keys greater than
fromKey should be included.</dd>
<dd><code>toKey</code> - is the upper bound of the key range, or null if the range
has no upper bound.</dd>
<dd><code>toInclusive</code> - is true if keys less than or equal to toKey should be
included in the key range, or false if only keys less than toKey should
be included.</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the cursor.</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
<a name="entities-com.sleepycat.je.Transaction-java.lang.Object-boolean-java.lang.Object-boolean-com.sleepycat.je.CursorConfig-">
<!-- -->
</a><a name="entities-com.sleepycat.je.Transaction-K-boolean-K-boolean-com.sleepycat.je.CursorConfig-">
<!-- -->
</a>
<ul class="blockListLast">
<li class="blockList">
<h4>entities</h4>
<pre>public&nbsp;<a href="../../../com/sleepycat/persist/EntityCursor.html" title="interface in com.sleepycat.persist">EntityCursor</a>&lt;E&gt;&nbsp;entities(<a href="../../../com/sleepycat/je/Transaction.html" title="class in com.sleepycat.je">Transaction</a>&nbsp;txn,
K&nbsp;fromKey,
boolean&nbsp;fromInclusive,
K&nbsp;toKey,
boolean&nbsp;toInclusive,
<a href="../../../com/sleepycat/je/CursorConfig.html" title="class in com.sleepycat.je">CursorConfig</a>&nbsp;config)
throws <a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></pre>
<div class="block"><span class="descfrmTypeLabel">Description copied from interface:&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html#entities-com.sleepycat.je.Transaction-K-boolean-K-boolean-com.sleepycat.je.CursorConfig-">EntityIndex</a></code></span></div>
<div class="block">Opens a cursor for traversing entities in a key range.</div>
<dl>
<dt><span class="overrideSpecifyLabel">Specified by:</span></dt>
<dd><code><a href="../../../com/sleepycat/persist/EntityIndex.html#entities-com.sleepycat.je.Transaction-K-boolean-K-boolean-com.sleepycat.je.CursorConfig-">entities</a></code>&nbsp;in interface&nbsp;<code><a href="../../../com/sleepycat/persist/EntityIndex.html" title="interface in com.sleepycat.persist">EntityIndex</a>&lt;K,E&gt;</code></dd>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>txn</code> - the transaction used to protect all operations performed with
the cursor, or null if the operations should not be transaction
protected. If the store is non-transactional, null must be specified.
For a transactional store the transaction is optional for read-only
access and required for read-write access.</dd>
<dd><code>fromKey</code> - is the lower bound of the key range, or null if the range
has no lower bound.</dd>
<dd><code>fromInclusive</code> - is true if keys greater than or equal to fromKey
should be included in the key range, or false if only keys greater than
fromKey should be included.</dd>
<dd><code>toKey</code> - is the upper bound of the key range, or null if the range
has no upper bound.</dd>
<dd><code>toInclusive</code> - is true if keys less than or equal to toKey should be
included in the key range, or false if only keys less than toKey should
be included.</dd>
<dd><code>config</code> - the cursor configuration that determines the default lock
mode used for all cursor operations, or null to implicitly use <a href="../../../com/sleepycat/je/CursorConfig.html#DEFAULT"><code>CursorConfig.DEFAULT</code></a>.</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the cursor.</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="../../../com/sleepycat/je/DatabaseException.html" title="class in com.sleepycat.je">DatabaseException</a></code> - the base class for all BDB exceptions.</dd>
</dl>
</li>
</ul>
</li>
</ul>
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</ul>
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