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<h2 class="title" style="clear: both"><a id="DBOpenFlags"></a>Database Open Flags</h2>
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<p>
The following are the flags that you may want to use at database open time.
Note that this list is not exhaustive — it includes only those flags likely
to be of interest for introductory, single-threaded
database applications. For a complete list of the flags available to you, see the
<i class="citetitle">Berkeley DB C++ API guide.</i>
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Note</h3>
<p>
To specify more than one flag on the call to
<span><tt class="methodname">Db::open()</tt>,</span>
you must bitwise inclusively OR them together:
</p>
<a id="c_db3"></a>
<pre class="programlisting">u_int32_t open_flags = DB_CREATE | DB_EXCL;</pre>
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<li>
<p>
<tt class="literal">DB_CREATE</tt>
</p>
<p>
If the database does not currently exist, create it. By default, the database open
fails if the database does not already exist.
</p>
</li>
<li>
<p>
<tt class="literal">DB_EXCL</tt>
</p>
<p>
Exclusive database creation. Causes the database open to fail if the database
already exists. This flag is only meaningful when used with
<tt class="literal">DB_CREATE</tt>.
</p>
</li>
<li>
<p>
<tt class="literal">DB_RDONLY</tt>
</p>
<p>
Open the database for read operations only. Causes any subsequent database write
operations to fail.
</p>
</li>
<li>
<p>
<tt class="literal">DB_TRUNCATE</tt>
</p>
<p>
Physically truncate (empty) the on-disk file that contains the database.
Causes DB to delete all databases physically contained in that file.
</p>
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