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<h2 class="title" style="clear: both"><a id="dbmultiplekeydatabuilder"></a>DbMultipleKeyDataBuilder</h2>
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<pre class="programlisting">#include <db_cxx.h>
class DbMultipleKeyDataBuilder
{
public:
DbMultipleKeyDataBuilder(Dbt &dbt);
bool append(void *kbuf, size_t klen, void *dbuf, size_t dlen);
bool reserve(void *&kdest, size_t klen, void *&ddest, size_t dlen);
}; </pre>
<p>
This class builds a bulk buffer for use when the
<a class="link" href="dbput.html#put_DB_MULTIPLE_KEY">DB_MULTIPLE_KEY</a>
flag is specified to either the
<a class="xref" href="dbput.html" title="Db::put()">Db::put()</a> or
<a class="xref" href="dbdel.html" title="Db::del()">Db::del()</a> methods with the btree
or hash access methods. The buffer in the
<a class="link" href="dbt.html" title="Chapter 4. The Dbt Handle">Dbt</a> passed to the constructor is
filled by calls to
<a class="xref" href="dbmultiplekeydatabuilder.html#dbmultiplekeydatabuilder.append" title="DbMultipleKeyDataBuilder.append()">DbMultipleKeyDataBuilder.append()</a>
or
<a class="xref" href="dbmultiplekeydatabuilder.html#dbmultiplekeydatabuilder.reserve" title="DbMultipleKeyDataBuilder.reserve()">DbMultipleKeyDataBuilder.reserve()</a>.
</p>
<p>
The constructor takes a <a class="xref" href="dbt.html" title="Chapter 4. The Dbt Handle">
The Dbt Handle
</a>
that must be configured to contain a buffer managed by the application,
with the <code class="literal">ulen</code> field set to the size of the buffer.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Note</h3>
<p>
All instances of the bulk retrieval classes may be used only once,
and to build the bulk buffer in the forward direction only.
</p>
</div>
<p>
Parameters are:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p>
<code class="literal">dbt</code>
</p>
<p>
The <span class="bold"><strong>dbt</strong></span> parameter is a <a class="xref" href="dbt.html" title="Chapter 4. The Dbt Handle">
The Dbt Handle
</a> that must already be configured to contain a buffer managed by the application, with the <code class="literal">ulen</code> field set to the size of the buffer, which must be a multiple of 4.
</p>
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<div class="sect2" lang="en" xml:lang="en">
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<div>
<h3 class="title"><a id="dbmultiplekeydatabuilder.append"></a>DbMultipleKeyDataBuilder.append()</h3>
</div>
</div>
</div>
<p>
The <code class="methodname">DbMultipleKeyDataBuilder.append()</code>
method copies a key/data pair to the end of the buffer.
</p>
<p>
The <code class="methodname">DbMultipleKeyDataBuilder.append()</code>
method returns <code class="literal">false</code> if the key/data
pair does not fit in the buffer and <code class="literal">true</code>
otherwise.
</p>
<p>
Parameters are:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p>
<code class="literal">kbuf</code>
</p>
<p>
A pointer to the key to be copied into the bulk buffer.
</p>
</li>
<li>
<p>
<code class="literal">klen</code>
</p>
<p>
The number of bytes of the key to be copied.
</p>
</li>
<li>
<p>
<code class="literal">dbuf</code>
</p>
<p>
A pointer to the data item to be copied into the bulk
buffer.
</p>
</li>
<li>
<p>
<code class="literal">dlen</code>
</p>
<p>
The number of bytes of the data item to be copied.
</p>
</li>
</ul>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="dbmultiplekeydatabuilder.reserve"></a>DbMultipleKeyDataBuilder.reserve()</h3>
</div>
</div>
</div>
<p>
The <code class="methodname">DbMultipleKeyDataBuilder.reserve()</code>
method reserves space for the next key/data pair in the bulk
buffer. Unlike the <code class="methodname">append()</code>, no data is
actually copied into the bulk buffer by
<code class="methodname">reserve()</code>: copying the data is the
responsibility of the application.
</p>
<p>
The <code class="methodname">DbMultipleKeyDataBuilder.reserve()</code>
method returns <code class="literal">false</code> if the data does
not fit in the buffer and <code class="literal">true</code> otherwise.
</p>
<p>
Parameters are:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p>
<code class="literal">kdest</code>
</p>
<p>
Set to a pointer to the position in the bulk buffer reserved for the key, if enough space is available.
</p>
</li>
<li>
<p>
<code class="literal">klen</code>
</p>
<p>
The number of bytes to reserve for the key.
</p>
</li>
<li>
<p>
<code class="literal">ddest</code>
</p>
<p>
Set to a pointer to the position in the bulk buffer reserved for the data item, if enough space is available.
</p>
</li>
<li>
<p>
<code class="literal">dlen</code>
</p>
<p>
The number of bytes to reserve for the data item.
</p>
</li>
</ul>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="id1662169"></a>Class</h3>
</div>
</div>
</div>
<p>
<a class="link" href="dbmultiplebuilder.html" title="DbMultipleBuilder">DbMultipleBuilder</a>
</p>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="id1662282"></a>See Also</h3>
</div>
</div>
</div>
<p>
<a class="xref" href="dbt.html#dbtlist" title="DBT and Bulk Operations">DBT and Bulk Operations</a>
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