some markup cleanup, better topic section name, fix XML validation error

<compatibility>Version 2.1 and higher</compatibility>

<summary>

    <p>mod_dbd manages SQL database connections using

    <p><module>mod_dbd</module> 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

    for both threaded and non-threaded MPMs.</p>

</summary>

<section id="reslist"><title>Connection Pooling</title>

<section id="pooling"><title>Connection Pooling</title>

    <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

    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"

    title="Connection pooling in Apache">this article at ApacheTutor</a>.

    mod_dbd supersedes the modules presented in that article.</p>

    >this article at ApacheTutor</a>. <module>mod_dbd</module> supersedes

    the modules presented in that article.</p>

</section>

<section id="API"><title>Apache DBD API</title>

    <p>mod_dbd exports three functions for other modules to use.

    The API is as follows:</p>

    <p><module>mod_dbd</module> exports three functions for other modules

    to use. The API is as follows:</p>

    <example>

<pre><code>typedef struct {

    apr_dbd_t *handle;

    apr_dbd_driver_t *driver;

/* 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*));

</code></pre>

APR_DECLARE_OPTIONAL_FN(ap_dbd_t*, ap_dbd_acquire, (request_rec*));</code></pre>

    </example>

</section>

<section id="prepared"><title>SQL Prepared Statements</title>

    <p>mod_dbd supports SQL prepared statements on behalf of

    modules that may wish to use them.  Each prepared statement

    <p><module>mod_dbd</module> 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.</p>

</section>

<directivesynopsis>

<name>DBDParams</name>

<description>Parameters for database connection</description>

<syntax>DBDParams <var>param1=value1,param2=value2</var></syntax>

<syntax>DBDParams

<var>param1</var>=<var>value1</var>[,<var>param2</var>=<var>value2</var>]</syntax>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<directivesynopsis>

<name>DBDPersist</name>

<description>Whether to use persistent connections</description>

<syntax>DBDPersist <var>[0|1]</var></syntax>

<syntax>DBDPersist 0|1</syntax>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

    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>

    platforms only).</p>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>DBDMax</name>

<description>Maximum number of connections</description>

</usage>

</directivesynopsis>

</modulesynopsis>