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<h2 class="title" style="clear: both"><a id="dbset_h_nelem"></a>Db::set_h_nelem()</h2>
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<pre class="programlisting">#include <db_cxx.h>
int
Db::set_h_nelem(u_int32_t h_nelem); </pre>
<p>
Set an estimate of the final size of the hash table.
</p>
<p>
In order for the estimate to be used when creating the database, the
<a class="xref" href="dbset_h_ffactor.html" title="Db::set_h_ffactor()">Db::set_h_ffactor()</a>
method must also be called. If the estimate or fill factor are not
set or are set too low, hash tables will still expand gracefully as
keys are entered, although a slight performance degradation may be
noticed.
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<p>
The <code class="methodname">Db::set_h_nelem()</code> method configures a database, not only
operations performed using the specified <a class="link" href="db.html" title="Chapter 2. The Db Handle">Db</a>
handle.
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The <code class="methodname">Db::set_h_nelem()</code> method may not be called after the
<a class="xref" href="dbopen.html" title="Db::open()">Db::open()</a> method is called. If
the database already exists when <a class="xref" href="dbopen.html" title="Db::open()">Db::open()</a>
is called, the information specified to <code class="methodname">Db::set_h_nelem()</code> will be ignored.
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<p>
The <code class="methodname">Db::set_h_nelem()</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.
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<h3 class="title"><a id="idp5641048"></a>Parameters</h3>
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<h4 class="title"><a id="idp5640352"></a>h_nelem</h4>
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<p>
The <span class="bold"><strong>h_nelem</strong></span> parameter is an estimate
of the final size of the hash table.
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<p>
The <code class="methodname">Db::set_h_nelem()</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:
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If the method was called after <a class="xref" href="dbopen.html" title="Db::open()">Db::open()</a>
was called; or if an invalid flag value or parameter was specified.
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<a class="link" href="db.html" title="Chapter 2. The Db Handle">Db</a>
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<h3 class="title"><a id="idp5641264"></a>See Also</h3>
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<a class="xref" href="db.html#dblist" title="Database and Related Methods">Database and Related Methods</a>
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