docs/manual/mod/mod_dbd.html.en - httpd - Git at Google

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 <p class="apache">Apache HTTP Server Version 2.3</p>
 <img alt="" src="../images/feather.gif" /></div>
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 <div id="page-content">
 <div id="preamble"><h1>Apache Module mod_dbd</h1>
 <div class="toplang">
 <p><span>Available Languages: </span><a href="../en/mod/mod_dbd.html" title="English">&nbsp;en&nbsp;</a></p>
 </div>
 <table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Manages SQL database connections</td></tr>
 <tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 <tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>dbd_module</td></tr>
 <tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_dbd.c</td></tr>
 <tr><th><a href="module-dict.html#Compatibility">Compatibility:</a></th><td>Version 2.1 and later</td></tr></table>
 <h3>Summary</h3>

     <p><code class="module"><a href="../mod/mod_dbd.html">mod_dbd</a></code> manages SQL database connections using
     <a href="http://people.apache.org/~niq/dbd.html">apr_dbd</a>.
     It provides database connections on request to modules
     requiring SQL database functions, and takes care of
     managing databases with optimal efficiency and scalability
     for both threaded and non-threaded MPMs.</p>
 </div>
 <div id="quickview"><h3 class="directives">Directives</h3>
 <ul id="toc">
 <li><img alt="" src="../images/down.gif" /> <a href="#dbdexptime">DBDExptime</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#dbdkeep">DBDKeep</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#dbdmax">DBDMax</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#dbdmin">DBDMin</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#dbdparams">DBDParams</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#dbdpersist">DBDPersist</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#dbdpreparesql">DBDPrepareSQL</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#dbdriver">DBDriver</a></li>
 </ul>
 <h3>Topics</h3>
 <ul id="topics">
 <li><img alt="" src="../images/down.gif" /> <a href="#pooling">Connection Pooling</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#API">Apache DBD API</a></li>
 <li><img alt="" src="../images/down.gif" /> <a href="#prepared">SQL Prepared Statements</a></li>
 </ul></div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="section">
 <h2><a name="pooling" id="pooling">Connection Pooling</a></h2>
     <p>This module manages database connections, in a manner
     optimised for the platform.  On non-threaded platforms,
     it provides a persistent connection in the manner of
     classic LAMP (Linux, Apache, Mysql, Perl/PHP/Python).
     On threaded platform, it provides an altogether more
     scalable and efficient <em>connection pool</em>, as
     described in <a href="http://www.apachetutor.org/dev/reslist">this article at ApacheTutor</a>. <code class="module"><a href="../mod/mod_dbd.html">mod_dbd</a></code> supersedes
     the modules presented in that article.</p>
 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="section">
 <h2><a name="API" id="API">Apache DBD API</a></h2>
     <p><code class="module"><a href="../mod/mod_dbd.html">mod_dbd</a></code> exports five functions for other modules
     to use. The API is as follows:</p>

     <div class="example"><pre><code>typedef struct {
     apr_dbd_t *handle;
     apr_dbd_driver_t *driver;
     apr_hash_t *prepared;
 } ap_dbd_t;

 /* Export functions to access the database */

 /* acquire a connection that MUST be explicitly closed.
  * Returns NULL on error
  */
 AP_DECLARE(ap_dbd_t*) ap_dbd_open(apr_pool_t*, server_rec*);

 /* release a connection acquired with ap_dbd_open */
 AP_DECLARE(void) ap_dbd_close(server_rec*, ap_dbd_t*);

 /* acquire a connection that will have the lifetime of a request
  * and MUST NOT be explicitly closed.  Return NULL on error.
  * This is the preferred function for most applications.
  */
 AP_DECLARE(ap_dbd_t*) ap_dbd_acquire(request_rec*);

 /* acquire a connection that will have the lifetime of a connection
  * and MUST NOT be explicitly closed.  Return NULL on error.
  */
 AP_DECLARE(ap_dbd_t*) ap_dbd_cacquire(request_rec*);

 /* Prepare a statement for use by a client module */
 AP_DECLARE(void) ap_dbd_prepare(server_rec*, const char*, const char*);

 /* Also export them as optional functions for modules that prefer it */
 APR_DECLARE_OPTIONAL_FN(ap_dbd_t*, ap_dbd_open, (apr_pool_t*, server_rec*));
 APR_DECLARE_OPTIONAL_FN(void, ap_dbd_close, (server_rec*, ap_dbd_t*));
 APR_DECLARE_OPTIONAL_FN(ap_dbd_t*, ap_dbd_acquire, (request_rec*));
 APR_DECLARE_OPTIONAL_FN(ap_dbd_t*, ap_dbd_cacquire, (conn_rec*));
 APR_DECLARE_OPTIONAL_FN(void, ap_dbd_prepare, (server_rec*, const char*, const char*));
 </code></pre></div>
 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="section">
 <h2><a name="prepared" id="prepared">SQL Prepared Statements</a></h2>
     <p><code class="module"><a href="../mod/mod_dbd.html">mod_dbd</a></code> supports SQL prepared statements on behalf
     of modules that may wish to use them.  Each prepared statement
     must be assigned a name (label), and they are stored in a hash:
     the <code>prepared</code> field of an <code>ap_dbd_t</code>.
     Hash entries are of type <code>apr_dbd_prepared_t</code>
     and can be used in any of the apr_dbd prepared statement
     SQL query or select commands.</p>

     <p>It is up to dbd user modules to use the prepared statements
     and document what statements can be specified in httpd.conf,
     or to provide their own directives and use <code>ap_dbd_prepare</code>.</p>
 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="DBDExptime" id="DBDExptime">DBDExptime</a> <a name="dbdexptime" id="dbdexptime">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Keepalive time for idle connections</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DBDExptime <var>time-in-seconds</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_dbd</td></tr>
 </table>
     <p>Set the time to keep idle connections alive where the number
     of connections specified in DBDKeep has been exceeded (threaded
     platforms only).</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="DBDKeep" id="DBDKeep">DBDKeep</a> <a name="dbdkeep" id="dbdkeep">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum sustainednumber of connections</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DBDKeep <var>number</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_dbd</td></tr>
 </table>
     <p>Set the maximum number of connections per process to be
     sustained, other than for handling peak demand (threaded
     platforms only).</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="DBDMax" id="DBDMax">DBDMax</a> <a name="dbdmax" id="dbdmax">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum number of connections</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DBDMax <var>number</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_dbd</td></tr>
 </table>
     <p>Set the hard maximum number of connections per process
     (threaded platforms only).</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="DBDMin" id="DBDMin">DBDMin</a> <a name="dbdmin" id="dbdmin">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Minimum number of connections</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DBDMin <var>number</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_dbd</td></tr>
 </table>
     <p>Set the minimum number of connections per process (threaded
     platforms only).</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="DBDParams" id="DBDParams">DBDParams</a> <a name="dbdparams" id="dbdparams">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Parameters for database connection</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DBDParams
 <var>param1</var>=<var>value1</var>[,<var>param2</var>=<var>value2</var>]</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_dbd</td></tr>
 </table>
     <p>As required by the underlying driver.  Typically this will be
     used to pass whatever cannot be defaulted amongst username,
     password, database name, hostname and port number for connection.</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="DBDPersist" id="DBDPersist">DBDPersist</a> <a name="dbdpersist" id="dbdpersist">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Whether to use persistent connections</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DBDPersist 0|1</code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_dbd</td></tr>
 </table>
     <p>If set to 0, persistent and pooled connections are disabled.
     A new database connection is opened when requested by a client,
     and closed immediately on release.  This option is for debugging
     and low-usage servers.</p>

     <p>The default is to enable a pool of persistent connections
     (or a single LAMP-style persistent connection in the case of a
     non-threaded server), and should almost always be used in operation.</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="DBDPrepareSQL" id="DBDPrepareSQL">DBDPrepareSQL</a> <a name="dbdpreparesql" id="dbdpreparesql">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Define an SQL prepared statement</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DBDPrepareSQL <var>"SQL statement"</var> <var>label</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_dbd</td></tr>
 </table>
     <p>For modules such as authentication that use repeatedly use a
     single SQL statement, optimum performance is achieved by preparing
     the statement at startup rather than every time it is used.
     This directive prepares an SQL statement and assigns it a label.</p>

 </div>
 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 <div class="directive-section"><h2><a name="DBDriver" id="DBDriver">DBDriver</a> <a name="dbdriver" id="dbdriver">Directive</a></h2>
 <table class="directive">
 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Specify an SQL driver</td></tr>
 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DBDriver <var>name</var></code></td></tr>
 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_dbd</td></tr>
 </table>
     <p>Selects an apr_dbd driver by name.  The driver must be installed
     on your system (on most systems, it will be a shared object or dll).
     For example, <code>DBDriver mysql</code> will select the MySQL
     driver in apr_dbd_mysql.so.</p>

 </div>
 </div>
 <div class="bottomlang">
 <p><span>Available Languages: </span><a href="../en/mod/mod_dbd.html" title="English">&nbsp;en&nbsp;</a></p>
 </div><div id="footer">
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	<p class="apache">Apache HTTP Server Version 2.3</p>
	<img alt="" src="../images/feather.gif" /></div>
	<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div>
	<div id="path">
	<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs-project/">Documentation</a> > <a href="../">Version 2.3</a> > <a href="./">Modules</a></div>
	<div id="page-content">
	<div id="preamble"><h1>Apache Module mod_dbd</h1>
	<div class="toplang">
	<p><span>Available Languages: </span><a href="../en/mod/mod_dbd.html" title="English"> en </a></p>
	</div>
	<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Manages SQL database connections</td></tr>
	<tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr>
	<tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>dbd_module</td></tr>
	<tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_dbd.c</td></tr>
	<tr><th><a href="module-dict.html#Compatibility">Compatibility:</a></th><td>Version 2.1 and later</td></tr></table>
	<h3>Summary</h3>

	<p><code class="module"><a href="../mod/mod_dbd.html">mod_dbd</a></code> manages SQL database connections using
	<a href="http://people.apache.org/~niq/dbd.html">apr_dbd</a>.
	It provides database connections on request to modules
	requiring SQL database functions, and takes care of
	managing databases with optimal efficiency and scalability
	for both threaded and non-threaded MPMs.</p>
	</div>
	<div id="quickview"><h3 class="directives">Directives</h3>
	<ul id="toc">
	<li><img alt="" src="../images/down.gif" /> <a href="#dbdexptime">DBDExptime</a></li>
	<li><img alt="" src="../images/down.gif" /> <a href="#dbdkeep">DBDKeep</a></li>
	<li><img alt="" src="../images/down.gif" /> <a href="#dbdmax">DBDMax</a></li>
	<li><img alt="" src="../images/down.gif" /> <a href="#dbdmin">DBDMin</a></li>
	<li><img alt="" src="../images/down.gif" /> <a href="#dbdparams">DBDParams</a></li>
	<li><img alt="" src="../images/down.gif" /> <a href="#dbdpersist">DBDPersist</a></li>
	<li><img alt="" src="../images/down.gif" /> <a href="#dbdpreparesql">DBDPrepareSQL</a></li>
	<li><img alt="" src="../images/down.gif" /> <a href="#dbdriver">DBDriver</a></li>
	</ul>
	<h3>Topics</h3>
	<ul id="topics">
	<li><img alt="" src="../images/down.gif" /> <a href="#pooling">Connection Pooling</a></li>
	<li><img alt="" src="../images/down.gif" /> <a href="#API">Apache DBD API</a></li>
	<li><img alt="" src="../images/down.gif" /> <a href="#prepared">SQL Prepared Statements</a></li>
	</ul></div>
	<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
	<div class="section">
	<h2><a name="pooling" id="pooling">Connection Pooling</a></h2>
	<p>This module manages database connections, in a manner
	optimised for the platform. On non-threaded platforms,
	it provides a persistent connection in the manner of
	classic LAMP (Linux, Apache, Mysql, Perl/PHP/Python).
	On threaded platform, it provides an altogether more
	scalable and efficient <em>connection pool</em>, as
	described in <a href="http://www.apachetutor.org/dev/reslist">this article at ApacheTutor</a>. <code class="module"><a href="../mod/mod_dbd.html">mod_dbd</a></code> supersedes
	the modules presented in that article.</p>
	</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
	<div class="section">
	<h2><a name="API" id="API">Apache DBD API</a></h2>
	<p><code class="module"><a href="../mod/mod_dbd.html">mod_dbd</a></code> exports five functions for other modules
	to use. The API is as follows:</p>

	<div class="example"><pre><code>typedef struct {
	apr_dbd_t *handle;
	apr_dbd_driver_t *driver;
	apr_hash_t *prepared;
	} ap_dbd_t;

	/* Export functions to access the database */

	/* acquire a connection that MUST be explicitly closed.
	* Returns NULL on error
	*/
	AP_DECLARE(ap_dbd_t) ap_dbd_open(apr_pool_t, server_rec*);

	/* release a connection acquired with ap_dbd_open */
	AP_DECLARE(void) ap_dbd_close(server_rec, ap_dbd_t);

	/* acquire a connection that will have the lifetime of a request
	* and MUST NOT be explicitly closed. Return NULL on error.
	* This is the preferred function for most applications.
	*/
	AP_DECLARE(ap_dbd_t) ap_dbd_acquire(request_rec);

	/* acquire a connection that will have the lifetime of a connection
	* and MUST NOT be explicitly closed. Return NULL on error.
	*/
	AP_DECLARE(ap_dbd_t) ap_dbd_cacquire(request_rec);

	/* Prepare a statement for use by a client module */
	AP_DECLARE(void) ap_dbd_prepare(server_rec, const char, const char*);

	/* Also export them as optional functions for modules that prefer it */
	APR_DECLARE_OPTIONAL_FN(ap_dbd_t, ap_dbd_open, (apr_pool_t, server_rec*));
	APR_DECLARE_OPTIONAL_FN(void, ap_dbd_close, (server_rec, ap_dbd_t));
	APR_DECLARE_OPTIONAL_FN(ap_dbd_t, ap_dbd_acquire, (request_rec));
	APR_DECLARE_OPTIONAL_FN(ap_dbd_t, ap_dbd_cacquire, (conn_rec));
	APR_DECLARE_OPTIONAL_FN(void, ap_dbd_prepare, (server_rec, const char, const char*));
	</code></pre></div>
	</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
	<div class="section">
	<h2><a name="prepared" id="prepared">SQL Prepared Statements</a></h2>
	<p><code class="module"><a href="../mod/mod_dbd.html">mod_dbd</a></code> supports SQL prepared statements on behalf
	of modules that may wish to use them. Each prepared statement
	must be assigned a name (label), and they are stored in a hash:
	the <code>prepared</code> field of an <code>ap_dbd_t</code>.
	Hash entries are of type <code>apr_dbd_prepared_t</code>
	and can be used in any of the apr_dbd prepared statement
	SQL query or select commands.</p>

	<p>It is up to dbd user modules to use the prepared statements
	and document what statements can be specified in httpd.conf,
	or to provide their own directives and use <code>ap_dbd_prepare</code>.</p>
	</div>
	<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
	<div class="directive-section"><h2><a name="DBDExptime" id="DBDExptime">DBDExptime</a> <a name="dbdexptime" id="dbdexptime">Directive</a></h2>
	<table class="directive">
	<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Keepalive time for idle connections</td></tr>
	<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DBDExptime <var>time-in-seconds</var></code></td></tr>
	<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
	<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
	<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_dbd</td></tr>
	</table>
	<p>Set the time to keep idle connections alive where the number
	of connections specified in DBDKeep has been exceeded (threaded
	platforms only).</p>

	</div>
	<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
	<div class="directive-section"><h2><a name="DBDKeep" id="DBDKeep">DBDKeep</a> <a name="dbdkeep" id="dbdkeep">Directive</a></h2>
	<table class="directive">
	<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum sustainednumber of connections</td></tr>
	<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DBDKeep <var>number</var></code></td></tr>
	<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
	<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
	<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_dbd</td></tr>
	</table>
	<p>Set the maximum number of connections per process to be
	sustained, other than for handling peak demand (threaded
	platforms only).</p>

	</div>
	<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
	<div class="directive-section"><h2><a name="DBDMax" id="DBDMax">DBDMax</a> <a name="dbdmax" id="dbdmax">Directive</a></h2>
	<table class="directive">
	<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum number of connections</td></tr>
	<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DBDMax <var>number</var></code></td></tr>
	<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
	<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
	<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_dbd</td></tr>
	</table>
	<p>Set the hard maximum number of connections per process
	(threaded platforms only).</p>

	</div>
	<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
	<div class="directive-section"><h2><a name="DBDMin" id="DBDMin">DBDMin</a> <a name="dbdmin" id="dbdmin">Directive</a></h2>
	<table class="directive">
	<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Minimum number of connections</td></tr>
	<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DBDMin <var>number</var></code></td></tr>
	<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
	<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
	<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_dbd</td></tr>
	</table>
	<p>Set the minimum number of connections per process (threaded
	platforms only).</p>

	</div>
	<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
	<div class="directive-section"><h2><a name="DBDParams" id="DBDParams">DBDParams</a> <a name="dbdparams" id="dbdparams">Directive</a></h2>
	<table class="directive">
	<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Parameters for database connection</td></tr>
	<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DBDParams
	<var>param1</var>=<var>value1</var>[,<var>param2</var>=<var>value2</var>]</code></td></tr>
	<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
	<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
	<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_dbd</td></tr>
	</table>
	<p>As required by the underlying driver. Typically this will be
	used to pass whatever cannot be defaulted amongst username,
	password, database name, hostname and port number for connection.</p>

	</div>
	<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
	<div class="directive-section"><h2><a name="DBDPersist" id="DBDPersist">DBDPersist</a> <a name="dbdpersist" id="dbdpersist">Directive</a></h2>
	<table class="directive">
	<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Whether to use persistent connections</td></tr>
	<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DBDPersist 0\|1</code></td></tr>
	<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
	<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
	<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_dbd</td></tr>
	</table>
	<p>If set to 0, persistent and pooled connections are disabled.
	A new database connection is opened when requested by a client,
	and closed immediately on release. This option is for debugging
	and low-usage servers.</p>

	<p>The default is to enable a pool of persistent connections
	(or a single LAMP-style persistent connection in the case of a
	non-threaded server), and should almost always be used in operation.</p>

	</div>
	<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
	<div class="directive-section"><h2><a name="DBDPrepareSQL" id="DBDPrepareSQL">DBDPrepareSQL</a> <a name="dbdpreparesql" id="dbdpreparesql">Directive</a></h2>
	<table class="directive">
	<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Define an SQL prepared statement</td></tr>
	<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DBDPrepareSQL <var>"SQL statement"</var> <var>label</var></code></td></tr>
	<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
	<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
	<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_dbd</td></tr>
	</table>
	<p>For modules such as authentication that use repeatedly use a
	single SQL statement, optimum performance is achieved by preparing
	the statement at startup rather than every time it is used.
	This directive prepares an SQL statement and assigns it a label.</p>

	</div>
	<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
	<div class="directive-section"><h2><a name="DBDriver" id="DBDriver">DBDriver</a> <a name="dbdriver" id="dbdriver">Directive</a></h2>
	<table class="directive">
	<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Specify an SQL driver</td></tr>
	<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DBDriver <var>name</var></code></td></tr>
	<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
	<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
	<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_dbd</td></tr>
	</table>
	<p>Selects an apr_dbd driver by name. The driver must be installed
	on your system (on most systems, it will be a shared object or dll).
	For example, <code>DBDriver mysql</code> will select the MySQL
	driver in apr_dbd_mysql.so.</p>

	</div>
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