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206 lines
8.2 KiB
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<title>DbMultipleKeyDataIterator</title>
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<link rel="up" href="dbt.html" title="Chapter 4. The Dbt Handle" />
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<link rel="prev" href="dbmultipledataiterator.html" title="DbMultipleDataIterator" />
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<p>Library Version 11.2.5.2</p>
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<table width="100%" summary="Navigation header">
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<tr>
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<th colspan="3" align="center">DbMultipleKeyDataIterator</th>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="dbmultipledataiterator.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 4.
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The Dbt Handle
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</th>
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<td width="20%" align="right"> <a accesskey="n" href="dbmultiplerecnodataiterator.html">Next</a></td>
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<div class="sect1" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h2 class="title" style="clear: both"><a id="dbmultiplekeydataiterator"></a>DbMultipleKeyDataIterator</h2>
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</div>
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</div>
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</div>
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<pre class="programlisting">#include <db_cxx.h>
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class DbMultipleKeyDataIterator
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{
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public:
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DbMultipleKeyDataIterator(const Dbt &dbt);
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bool next(Dbt &key, Dbt &data);
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}; </pre>
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<p>
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If either of the
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<a class="link" href="dbcget.html#dbcget_DB_MULTIPLE">DB_MULTIPLE</a>
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or
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<a class="link" href="dbcget.html#dbcget_DB_MULTIPLE_KEY">DB_MULTIPLE_KEY</a>
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flags were specified to the <a class="xref" href="dbget.html" title="Db::get()">Db::get()</a> or
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<a class="xref" href="dbcget.html" title="Dbc::get()">Dbc::get()</a> methods, the data
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<a class="link" href="dbt.html" title="Chapter 4. The Dbt Handle">Dbt</a> returned by those interfaces will
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refer to a buffer that is filled with data. Access to that data is through these
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classes.
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</p>
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<p>
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The <code class="classname">DbMultipleDataIterator</code> class is used to iterate through data
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returned using the
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<a class="link" href="dbcget.html#dbcget_DB_MULTIPLE_KEY">DB_MULTIPLE_KEY</a>
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flag from a database belonging to Btree or Hash access methods.
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</p>
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<p>
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The constructor takes the <a class="xref" href="dbt.html" title="Chapter 4. The Dbt Handle">
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The Dbt Handle
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</a>
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returned by the call to <a class="xref" href="dbget.html" title="Db::get()">Db::get()</a>
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or <a class="xref" href="dbcget.html" title="Dbc::get()">Dbc::get()</a> that used the
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<a class="link" href="dbcget.html#dbcget_DB_MULTIPLE_KEY">DB_MULTIPLE_KEY</a>
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flag.
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</p>
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<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
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<h3 class="title">Note</h3>
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<p>
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All instances of the bulk retrieval classes may be used only
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once, and to traverse the bulk retrieval buffer in the forward
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direction only. However, they are nondestructive, so multiple
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iterators can be instantiated and used on the same returned
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data <a class="link" href="dbt.html" title="Chapter 4. The Dbt Handle">Dbt</a>.
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</p>
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</div>
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<p>
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Parameters are:
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</p>
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<div class="itemizedlist">
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<ul type="disc">
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<li>
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<p>
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<code class="literal">dbt</code>
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</p>
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<p>
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The <span class="bold"><strong>dbt</strong></span> parameter is a
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data <a class="xref" href="dbt.html" title="Chapter 4. The Dbt Handle">
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The Dbt Handle
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</a>
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returned by the call to <a class="xref" href="dbget.html" title="Db::get()">Db::get()</a>
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or <a class="xref" href="dbcget.html" title="Dbc::get()">Dbc::get()</a> that used the
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<a class="link" href="dbcget.html#dbcget_DB_MULTIPLE_KEY">DB_MULTIPLE_KEY</a>
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flag.
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</p>
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</li>
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</ul>
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</div>
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<div class="sect2" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h3 class="title"><a id="dbmultiplekeydataiterator.next"></a>DbMultipleKeyDataIterator.next()</h3>
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</div>
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</div>
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</div>
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<p>
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The <code class="methodname">DbMultipleKeyDataIterator.next()</code> method
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returns the next data item in the original bulk retrieval buffer.
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</p>
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<p>
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The <code class="methodname">DbMultipleKeyDataIterator.next()</code> method
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method returns <code class="literal">false</code> if no more data are available, and
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<code class="literal">true</code> otherwise.
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</p>
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<p>
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Parameters are:
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</p>
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<div class="itemizedlist">
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<ul type="disc">
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<li>
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<p>
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<code class="literal">key</code>
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</p>
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<p>
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The <span class="bold"><strong>key</strong></span> parameter is a
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<a class="xref" href="dbt.html" title="Chapter 4. The Dbt Handle">
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The Dbt Handle
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</a>
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that will be filled in with a reference to a buffer, a
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size, and an offset that together yield the next data item
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in the original bulk retrieval buffer.
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</p>
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</li>
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<li>
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<p>
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<code class="literal">data</code>
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</p>
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<p>
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The <span class="bold"><strong>data</strong></span> parameter is a
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<a class="xref" href="dbt.html" title="Chapter 4. The Dbt Handle">
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The Dbt Handle
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</a>
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that will be filled in with a reference to a buffer, a
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size, and an offset that together yield the next data item
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in the original bulk retrieval buffer.
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</p>
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</li>
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</ul>
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</div>
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</div>
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<div class="sect2" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h3 class="title"><a id="id3590621"></a>Class</h3>
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</div>
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</div>
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</div>
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<p>
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<a class="link" href="dbmultipleiterator.html" title="DbMultipleIterator">DbMultipleIterator</a>
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</p>
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</div>
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<div class="sect2" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h3 class="title"><a id="id3590542"></a>See Also</h3>
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</div>
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</div>
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</div>
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<p>
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<a class="xref" href="dbt.html#dbtlist" title="DBT and Bulk Operations">DBT and Bulk Operations</a>
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</p>
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</div>
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</div>
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<div class="navfooter">
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<hr />
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<table width="100%" summary="Navigation footer">
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<tr>
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<td width="40%" align="left"><a accesskey="p" href="dbmultipledataiterator.html">Prev</a> </td>
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<td width="20%" align="center">
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<a accesskey="u" href="dbt.html">Up</a>
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</td>
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<td width="40%" align="right"> <a accesskey="n" href="dbmultiplerecnodataiterator.html">Next</a></td>
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</tr>
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<tr>
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<td width="40%" align="left" valign="top">DbMultipleDataIterator </td>
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<td width="20%" align="center">
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<a accesskey="h" href="index.html">Home</a>
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</td>
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</html>
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