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java.lang.Object com.sleepycat.bind.tuple.TupleBase<E> com.sleepycat.bind.tuple.TupleTupleKeyCreator<E>
public abstract class TupleTupleKeyCreator<E>
An abstract key creator that uses a tuple key and a tuple data entry. This
class takes care of converting the key and data entry to/from TupleInput
and TupleOutput
objects.
The following abstract method must be implemented by a concrete subclass
to create the index key using these objects
If ForeignKeyDeleteAction.NULLIFY
was
specified when opening the secondary database, the following method must be
overridden to nullify the foreign index key. If NULLIFY was not specified,
this method need not be overridden.
If ForeignKeyDeleteAction.NULLIFY
was
specified when creating the secondary, this method is called when the
entity for this foreign key is deleted. If NULLIFY was not specified,
this method will not be called and may always return false.
Constructor Summary | |
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TupleTupleKeyCreator()
Creates a tuple-tuple key creator. |
Method Summary | |
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boolean |
createSecondaryKey(SecondaryDatabase db,
DatabaseEntry primaryKeyEntry,
DatabaseEntry dataEntry,
DatabaseEntry indexKeyEntry)
Creates a secondary key entry, given a primary key and data entry. |
abstract boolean |
createSecondaryKey(TupleInput primaryKeyInput,
TupleInput dataInput,
TupleOutput indexKeyOutput)
Creates the index key from primary key tuple and data tuple. |
boolean |
nullifyForeignKey(SecondaryDatabase db,
DatabaseEntry dataEntry)
Sets the foreign key reference to null in the datum of the primary database. |
boolean |
nullifyForeignKey(TupleInput dataInput,
TupleOutput dataOutput)
Clears the index key in the tuple data entry. |
Methods inherited from class com.sleepycat.bind.tuple.TupleBase |
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entryToInput, getTupleBufferSize, getTupleOutput, inputToEntry, newOutput, newOutput, outputToEntry, setTupleBufferSize |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public TupleTupleKeyCreator()
Method Detail |
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public boolean createSecondaryKey(SecondaryDatabase db, DatabaseEntry primaryKeyEntry, DatabaseEntry dataEntry, DatabaseEntry indexKeyEntry)
SecondaryKeyCreator
A secondary key may be derived from the primary key, primary data, or a combination of the primary key and data. For secondary keys that are optional, the key creator method may return false and the key/data pair will not be indexed. To ensure the integrity of a secondary database the key creator method must always return the same result for a given set of input parameters.
createSecondaryKey
in interface SecondaryKeyCreator
db
- the database to which the secondary key will be added.
This parameter is passed for informational purposes but is not commonly
used.
primaryKeyEntry
- the primary key entry. This parameter must not be modified
by this method.
dataEntry
- the primary data entry. This parameter must not be modified
by this method.
indexKeyEntry
- the secondary key created by this method.
public boolean nullifyForeignKey(SecondaryDatabase db, DatabaseEntry dataEntry)
ForeignKeyNullifier
nullifyForeignKey
in interface ForeignKeyNullifier
db
- the database in which the foreign key integrity
constraint is defined. This parameter is passed for informational
purposes but is not commonly used.dataEntry
- the existing primary datum in which the foreign key
reference should be set to null. This parameter should be updated by
this method if it returns true.
public abstract boolean createSecondaryKey(TupleInput primaryKeyInput, TupleInput dataInput, TupleOutput indexKeyOutput)
primaryKeyInput
- is the TupleInput
for the primary key
entry.dataInput
- is the TupleInput
for the data entry.indexKeyOutput
- is the destination index key tuple.
public boolean nullifyForeignKey(TupleInput dataInput, TupleOutput dataOutput)
The secondary key should be output or removed by this method such
that createSecondaryKey(com.sleepycat.db.SecondaryDatabase, com.sleepycat.db.DatabaseEntry, com.sleepycat.db.DatabaseEntry, com.sleepycat.db.DatabaseEntry)
will return false. Other fields in the
data object should remain unchanged.
dataInput
- is the TupleInput
for the data entry.dataOutput
- is the destination TupleOutput
.
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