<?xml version="1.0" encoding="UTF-8" standalone="no"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>Database Open Flags</title> <link rel="stylesheet" href="gettingStarted.css" type="text/css" /> <meta name="generator" content="DocBook XSL Stylesheets V1.62.4" /> <link rel="home" href="index.html" title="Getting Started with Berkeley DB" /> <link rel="up" href="DB.html" title="Chapter 2. Databases" /> <link rel="previous" href="coredbclose.html" title="Closing Databases" /> <link rel="next" href="CoreDBAdmin.html" title="Administrative Methods" /> </head> <body> <div class="navheader"> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center">Database Open Flags</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="coredbclose.html">Prev</a> </td> <th width="60%" align="center">Chapter 2. Databases</th> <td width="20%" align="right"> <a accesskey="n" href="CoreDBAdmin.html">Next</a></td> </tr> </table> <hr /> </div> <div class="sect1" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h2 class="title" style="clear: both"><a id="DBOpenFlags"></a>Database Open Flags</h2> </div> </div> <div></div> </div> <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> </div> <div class="itemizedlist"> <ul type="disc"> <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> </li> </ul> </div> </div> <div class="navfooter"> <hr /> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"><a accesskey="p" href="coredbclose.html">Prev</a> </td> <td width="20%" align="center"> <a accesskey="u" href="DB.html">Up</a> </td> <td width="40%" align="right"> <a accesskey="n" href="CoreDBAdmin.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">Closing Databases </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> Administrative Methods</td> </tr> </table> </div> </body> </html>