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Release 5.2.28 on 6/10/2011
2011-09-13 17:44:24 +00:00
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<th colspan="3" align="center">Db::put()</th>
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The Db Handle
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<div class="sect1" lang="en" xml:lang="en">
<div class="titlepage">
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<div>
<h2 class="title" style="clear: both"><a id="dbput"></a>Db::put()</h2>
</div>
</div>
</div>
<pre class="programlisting">#include &lt;db_cxx.h&gt;
int
Db::put(DbTxn *txnid, Dbt *key, Dbt *data, u_int32_t flags);</pre>
<p>
The <code class="methodname">Db::put()</code> method stores key/data
pairs in the database. The default behavior of the
<code class="methodname">Db::put()</code> function is to enter the new
key/data pair, replacing any previously existing key if duplicates
are disallowed, or adding a duplicate data item if duplicates are
allowed. If the database supports duplicates, the
<code class="methodname">Db::put()</code> method adds the new data value
at the end of the duplicate set. If the database supports sorted
duplicates, the new data value is inserted at the correct sorted
location.
</p>
<p>
Unless otherwise specified, the
<code class="methodname">Db::put()</code> <span>
<span>
method either returns a non-zero error value or throws an
exception that encapsulates a non-zero error value on
failure, and returns 0 on success.
</span>
</span>
</p>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="id3589185"></a>Parameters</h3>
</div>
</div>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="id3589175"></a>txnid</h4>
</div>
</div>
</div>
<p>
If the operation is part of an application-specified
transaction, the <span class="bold"><strong>txnid</strong></span>
parameter is a transaction handle returned from
<a class="xref" href="txnbegin.html" title="DbEnv::txn_begin()">DbEnv::txn_begin()</a>; if
the operation is part of a Berkeley DB Concurrent Data
Store group, the <span class="bold"><strong>txnid</strong></span>
parameter is a handle returned from
<a class="xref" href="envcdsgroup_begin.html" title="DbEnv::cdsgroup_begin()">DbEnv::cdsgroup_begin()</a>;
otherwise NULL. If no transaction handle is specified,
but the operation occurs in a transactional database, the
operation will be implicitly transaction protected.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="id3588750"></a>key</h4>
</div>
</div>
</div>
<p>
The key <a class="link" href="dbt.html" title="Chapter 4.  The Dbt Handle">Dbt</a> operated on.
</p>
<p>
If creating a new record in a Heap database, the
key <a class="link" href="dbt.html" title="Chapter 4.  The Dbt Handle">Dbt</a>
must be empty. The <code class="literal">put</code>
method will return the new record's
<a class="link" href="db_heap_rid.html" title="DbHeapRecordId">Record ID (RID)</a>
in the key <a class="link" href="dbt.html" title="Chapter 4.  The Dbt Handle">Dbt</a>.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="id3588921"></a>data</h4>
</div>
</div>
</div>
<p>
The data <a class="link" href="dbt.html" title="Chapter 4.  The Dbt Handle">Dbt</a> operated on.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="id3588934"></a>flags</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>flags</strong></span> parameter must be set to 0
or one of the following values:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p><a id="dbput_DB_APPEND"></a>
<code class="literal">DB_APPEND</code>
</p>
<p>
Append the key/data pair to the end of the
database. For the DB_APPEND flag to be specified,
the underlying database must be a Heap, Queue or
Recno database. The record number allocated to
the record is returned in the specified
<span class="bold"><strong>key</strong></span>.
</p>
<p>
There is a minor behavioral difference between the Recno
and Queue access methods for the DB_APPEND flag. If a
transaction enclosing a
<code class="methodname">Db::put()</code> operation with the
DB_APPEND flag aborts, the record number may be
reallocated in a subsequent <code class="literal">DB_APPEND</code>
operation if you are using the Recno access method, but it
will not be reallocated if you are using the Queue access
method.
</p>
<p>
For a Heap database, if the put operation results
in the creation of a new record, then this flag is
required.
</p>
</li>
<li>
<p><a id="put_DB_NODUPDATA"></a>
<code class="literal">DB_NODUPDATA</code>
</p>
<p>
In the case of the Btree and Hash access methods,
enter the new key/data pair only if it does not
already appear in the database.
</p>
<p>
The DB_NODUPDATA flag may only be specified if the
underlying database has been configured to support
sorted duplicates. The DB_NODUPDATA flag may not
be specified to the Queue or Recno access methods.
</p>
<p>
The <code class="methodname">Db::put()</code> method will return
<a class="xref" href="dbcput.html#dbcput_DB_KEYEXIST" title="DB_KEYEXIST">DB_KEYEXIST</a>
if DB_NODUPDATA is set and the key/data pair already appears in the
database.
</p>
</li>
<li>
<p><a id="put_DB_NOOVERWRITE"></a>
<code class="literal">DB_NOOVERWRITE</code>
</p>
<p>
Enter the new key/data pair only if the key does
not already appear in the database. The
<code class="methodname">Db::put()</code> method call
with the DB_NOOVERWRITE flag set will fail if the
key already exists in the database, even if the
database supports duplicates.
</p>
<p>
The <code class="methodname">Db::put()</code> method will return
<a class="xref" href="dbcput.html#dbcput_DB_KEYEXIST" title="DB_KEYEXIST">DB_KEYEXIST</a>
if DB_NOOVERWRITE is set and the key already appears in the database.
</p>
<p>
This enforcement of uniqueness of keys applies only
to the primary key. The behavior of insertions
into secondary databases is not affected by the
DB_NOOVERWRITE flag. In particular, the insertion
of a record that would result in the creation of a
duplicate key in a secondary database that allows
duplicates would not be prevented by the use of
this flag.
</p>
</li>
<li>
<p><a id="put_DB_MULTIPLE"></a>
<code class="literal">DB_MULTIPLE</code>
</p>
<p>
Put multiple data items using keys from the buffer
to which the <span class="bold"><strong>key</strong></span>
parameter refers and data values from the buffer to
which the <span class="bold"><strong>data</strong></span>
parameter refers.
</p>
<p>
To put records in bulk with the btree or hash
access methods, construct bulk buffers in the
<span class="bold"><strong>key</strong></span> and <span class="bold"><strong>data</strong></span> <a class="link" href="dbt.html" title="Chapter 4.  The Dbt Handle">Dbt</a> using <a class="xref" href="dbmultipledatabuilder.html" title="DbMultipleDataBuilder">DbMultipleDataBuilder</a>. To
put records in bulk with the recno or queue access
methods, construct bulk buffers in the <span class="bold"><strong>data</strong></span> <a class="link" href="dbt.html" title="Chapter 4.  The Dbt Handle">Dbt</a> as before, but
construct the <span class="bold"><strong>key</strong></span>
<a class="link" href="dbt.html" title="Chapter 4.  The Dbt Handle">Dbt</a> using <a class="xref" href="dbmultiplerecnodatabuilder.html" title="DbMultipleRecnoDataBuilder">DbMultipleRecnoDataBuilder</a>
with a data size of zero.
</p>
<p>
A successful bulk operation is logically equivalent
to a loop through each key/data pair, performing a
<a class="xref" href="dbput.html" title="Db::put()">Db::put()</a> for each one.
</p>
<p>
See
<a class="xref" href="dbt.html#dbtlist" title="DBT and Bulk Operations">DBT and Bulk Operations</a>
for more information on working with bulk
updates.
</p>
<p>
The <code class="literal">DB_MULTIPLE</code> flag may only be
used alone, or with the
<code class="literal">DB_OVERWRITE_DUP</code> option.
</p>
</li>
<li>
<p><a id="put_DB_MULTIPLE_KEY"></a>
<code class="literal">DB_MULTIPLE_KEY</code>
</p>
<p>
Put multiple data items using keys and data from
the buffer to which the <span class="bold"><strong>key</strong></span> parameter refers.
</p>
<p>
To put records in bulk with the btree or hash
access methods, construct a bulk buffer in the
<span class="bold"><strong>key</strong></span> <a class="link" href="dbt.html" title="Chapter 4.  The Dbt Handle">Dbt</a> using <a class="xref" href="dbmultiplekeydatabuilder.html" title="DbMultipleKeyDataBuilder">DbMultipleKeyDataBuilder</a>.
To put records in bulk with the recno or queue
access methods, construct a bulk
buffer in the <span class="bold"><strong>key</strong></span>
<a class="link" href="dbt.html" title="Chapter 4.  The Dbt Handle">Dbt</a> using <a class="xref" href="dbmultiplerecnodatabuilder.html" title="DbMultipleRecnoDataBuilder">DbMultipleRecnoDataBuilder</a>.
</p>
<p>
See <a class="xref" href="dbt.html#dbtlist" title="DBT and Bulk Operations">DBT and Bulk Operations</a> for more information on working with bulk
updates.
</p>
<p>
The <code class="literal">DB_MULTIPLE_KEY</code> flag may
only be used alone, or with the
<code class="literal">DB_OVERWRITE_DUP</code> option.
</p>
</li>
<li>
<p><a id="put_DB_OVERWRITE_DUP"></a>
<code class="literal">DB_OVERWRITE_DUP</code>
</p>
<p>
Ignore duplicate records when overwriting records
in a database configured for sorted duplicates.
</p>
<p>
Normally, if a database is configured for sorted
duplicates, an attempt to put a record that
compares identically to a record already existing
in the database will fail. Using this flag causes
the put to silently proceed, without failure.
</p>
<p>
This flag is extremely useful when performing bulk
puts (using the <code class="literal">DB_MULTIPLE</code> or
<code class="literal">DB_MULTIPLE_KEY</code> flags).
Depending on the number of records you are writing
to the database with a bulk put, you may not want
the operation to fail in the event that a
duplicate record is encountered. Using this flag
along with the <code class="literal">DB_MULTIPLE</code> or
<code class="literal">DB_MULTIPLE_KEY</code> flags allows
the bulk put to complete, even if a duplicate
record is encountered.
</p>
<p>
This flag is also useful if you are using a custom
comparison function that compares only part of the
data portion of a record. In this case, two
records can compare equally when, in fact, they
are not equal. This flag allows the put to
complete, even if your custom comparison routine
claims the two records are equal.
</p>
</li>
</ul>
</div>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="id3589475"></a>Errors</h3>
</div>
</div>
</div>
<p>
The <code class="methodname">Db::put()</code> <span>
<span>
method may fail and throw a <a class="link" href="dbexception.html" title="Chapter 6. The DbException Class">DbException</a>
exception, encapsulating one of the following non-zero errors, or return one
of the following non-zero errors:
</span>
</span>
</p>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="id3589425"></a>DB_FOREIGN_CONFLICT</h4>
</div>
</div>
</div>
<p>
A <a class="link" href="dbassociate_foreign.html" title="Db::associate_foreign()">foreign key constraint violation</a>
has occurred. This can be caused by one of two things:
</p>
<div class="orderedlist">
<ol type="1">
<li>
<p>
An attempt was made to add a record to a
constrained database, and the key used for that
record does not exist in the foreign key
database.
</p>
</li>
<li>
<p>
<a class="link" href="dbassociate_foreign.html#associate_foreign_DB_FOREIGN_ABORT">DB_FOREIGN_ABORT</a>
was declared for a foreign key database, and then
subsequently a record was deleted from the
foreign key database without first removing it
from the constrained secondary database.
</p>
</li>
</ol>
</div>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="id3589413"></a>DB_HEAP_FULL</h4>
</div>
</div>
</div>
<p>
An attempt was made to add or update a record in a Heap
database. However, the size of the database was constrained
using the
<a class="xref" href="dbset_heapsize.html" title="Db::set_heapsize()">Db::set_heapsize()</a>
method, and that limit has been reached.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="id3588021"></a><span>DbDeadlockException or </span>DB_LOCK_DEADLOCK</h4>
</div>
</div>
</div>
<p>
A transactional database environment operation was selected to resolve
a deadlock.
</p>
<p>
<a class="xref" href="dbdeadlock.html" title="DbDeadlockException">DbDeadlockException</a> is thrown if
your Berkeley DB API is configured to throw exceptions.
Otherwise, <code class="literal">DB_LOCK_DEADLOCK</code> is returned.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="id3589623"></a><span>DbLockNotGrantedException or </span>DB_LOCK_NOTGRANTED</h4>
</div>
</div>
</div>
<p>
A Berkeley DB Concurrent Data Store database environment configured
for lock timeouts was unable to grant a lock in the allowed time.
</p>
<p>
<a class="xref" href="dblocknotgranted.html" title="DbLockNotGrantedException">DbLockNotGrantedException</a> is thrown if
your Berkeley DB API is configured to throw exceptions.
Otherwise, <code class="literal">DB_LOCK_NOTGRANTED</code> is returned.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="id3589400"></a> <span>DbRepHandleDeadException or</span> DB_REP_HANDLE_DEAD</h4>
</div>
</div>
</div>
<p>
When a client synchronizes with the master, it is possible for committed
transactions to be rolled back. This invalidates all the database and cursor
handles opened in the replication environment. Once this occurs, an attempt to use
such a handle will
<span>
throw a <a class="xref" href="dbrephandledead.html" title="DbRepHandleDeadException">DbRepHandleDeadException</a> (if
your application is configured to throw exceptions), or
</span>
return <code class="literal">DB_REP_HANDLE_DEAD</code>.
The application will need to discard the handle and open a new one in order to
continue processing.
</p>
</div>
<a id="dbput_DB_REP_LOCKOUT"></a>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="id3590018"></a><span>DbDeadlockException or </span>DB_REP_LOCKOUT</h4>
</div>
</div>
</div>
<p>
The operation was blocked by client/master synchronization.
</p>
<p>
<a class="xref" href="dbdeadlock.html" title="DbDeadlockException">DbDeadlockException</a> is thrown if
your Berkeley DB API is configured to throw exceptions.
Otherwise, <code class="literal">DB_REP_LOCKOUT</code> is returned.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="id3590050"></a>EACCES</h4>
</div>
</div>
</div>
<p>
An attempt was made to modify a read-only database.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="id3589985"></a>EINVAL</h4>
</div>
</div>
</div>
<p>
If a record number of 0 was specified; an attempt was made to add a
record to a fixed-length database that was too large to fit; an
attempt was made to do a partial put; an attempt was made to add a
record to a secondary index; or if an invalid flag value or parameter
was specified.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="id3589231"></a>ENOSPC</h4>
</div>
</div>
</div>
<p>
A btree exceeded the maximum btree depth (255).
</p>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="id3589236"></a>Class</h3>
</div>
</div>
</div>
<p>
<a class="link" href="db.html" title="Chapter 2.  The Db Handle">Db</a>
</p>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="id3589196"></a>See Also</h3>
</div>
</div>
</div>
<p>
<a class="xref" href="db.html#dblist" title="Database and Related Methods">Database and Related Methods</a>
</p>
</div>
</div>
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