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 <reference xml:id="ref.pdo-mysql" xmlns="http://docbook.org/ns/docbook">
  <?phpdoc extension-membership="bundledexternal" ?>
  <title>MySQL PDO Driver (PDO_MYSQL)</title>
  <titleabbrev>MySQL PDO Driver</titleabbrev>
  <partintro>

   <section xml:id="ref.pdo-mysql.intro">
   &reftitle.intro;
    <para>
     PDO_MYSQL is a driver that implements the <link linkend="intro.pdo">PHP
     Data Objects (PDO) interface</link>
     to enable access from PHP to MySQL databases.
    </para>
    <para>
     PDO_MYSQL uses emulated prepares by default.
    </para>

    <para>
      <emphasis role="bold">MySQL 8</emphasis>
    </para>

    <para>
     When running a PHP version before 7.1.16, or PHP 7.2 before 7.2.4, set
     MySQL 8 Server's default password plugin to <emphasis>mysql_native_password</emphasis>
     or else you will see errors similar to
     <emphasis>The server requested authentication method unknown to the client [caching_sha2_password]</emphasis>
     even when <emphasis>caching_sha2_password</emphasis> is not used.
    </para>
    <para>
     This is because MySQL 8 defaults to caching_sha2_password, a plugin that is
     not recognized by the older PHP (mysqlnd) releases. Instead, change it by
     setting <literal>default_authentication_plugin=mysql_native_password</literal>
     in <filename>my.cnf</filename>. The <emphasis>caching_sha2_password</emphasis>
     plugin is fully supported as of PHP 7.4.4. For older releases, the
     <link linkend="book.mysql-xdevapi">mysql_xdevapi</link> extension does
     support it.
    </para>

    <warning>
     <para>
      Beware: Some MySQL table types (storage engines) do not support transactions.  When
      writing transactional database code using a table type that does not support
      transactions, MySQL will pretend that a transaction was initiated successfully.
      In addition, any DDL queries issued will implicitly
      commit any pending transactions.
     </para>
    </warning>
    <note>
     <para>
      The MySQL driver does not properly support <constant>PDO::PARAM_INPUT_OUTPUT</constant>
      via <methodname>PDOStatement::bindParam</methodname>; while such parameters can be used,
      they are not updated (i.e. the actual output is ignored).
     </para>
    </note>
   </section>
   &reference.pdo-mysql.configure;
   &reference.pdo-mysql.constants;
   &reference.pdo-mysql.ini;
  </partintro>

  <refentry xml:id="ref.pdo-mysql.connection">
   <refnamediv>
    <refname>PDO_MYSQL DSN</refname>
    <refpurpose>Connecting to MySQL databases</refpurpose>
   </refnamediv>

   <refsect1 role="description">
    &reftitle.description;
    <para>
     The PDO_MYSQL Data Source Name (DSN) is composed of the following elements:
     <variablelist>
      <varlistentry>
       <term>DSN prefix</term>
       <listitem>
        <para>
        The DSN prefix is <userinput>mysql:</userinput>.
        </para>
       </listitem>
      </varlistentry>
      <varlistentry>
       <term><literal>host</literal></term>
       <listitem>
        <para>
         The hostname on which the database server resides.
        </para>
       </listitem>
      </varlistentry>
      <varlistentry>
       <term><literal>port</literal></term>
       <listitem>
        <para>
         The port number where the database server is listening.
        </para>
       </listitem>
      </varlistentry>
      <varlistentry>
       <term><literal>dbname</literal></term>
       <listitem>
        <para>
         The name of the database.
        </para>
       </listitem>
      </varlistentry>
      <varlistentry>
       <term><literal>user</literal></term>
       <listitem>
        <simpara>
         The name of the user for the connection. If you specify the user name
         in the DSN and pass it as the second argument, PDO ignores the value of
         the user name in DSN.
        </simpara>
       </listitem>
      </varlistentry>
      <varlistentry>
       <term><literal>password</literal></term>
       <listitem>
        <simpara>
         The password of the user for the connection. If you specify the
         password in the DSN and pass it as the third argument, PDO ignores the
         value of the password in DSN.
        </simpara>
       </listitem>
      </varlistentry>
      <varlistentry>
       <term><literal>unix_socket</literal></term>
       <listitem>
        <para>
         The MySQL Unix socket (shouldn't be used with <literal>host</literal>
         or <literal>port</literal>).
        </para>
       </listitem>
      </varlistentry>
      <varlistentry>
       <term><literal>charset</literal></term>
       <listitem>
        <para>
         The character set. See the <link linkend="mysqlinfo.concepts.charset">character set</link>
         concepts documentation for more information.
        </para>
       </listitem>
      </varlistentry>
     </variablelist>
    </para>
   </refsect1>

   <refsect1 role="examples">
    &reftitle.examples;
    <para>
     <example>
      <title>PDO_MYSQL DSN examples</title>
      <para>
       The following example shows a PDO_MYSQL DSN for connecting to
       MySQL databases:
       <programlisting>
<![CDATA[
mysql:host=localhost;dbname=testdb
]]>
       </programlisting>
       More complete examples:
       <programlisting>
<![CDATA[
mysql:host=localhost;port=3307;dbname=testdb
mysql:unix_socket=/tmp/mysql.sock;dbname=testdb
]]>
       </programlisting>
      </para>
     </example>
    </para>
   </refsect1>

   <refsect1 role="notes">
    &reftitle.notes;
    <note>
     <title>Unix only:</title>
     <para>
      When the host name is set to <literal>"localhost"</literal>, then the connection to the
      server is made through a domain socket. If PDO_MYSQL is compiled against libmysqlclient then the
      location of the socket file is at libmysqlclient's compiled in location. If PDO_MYSQL is compiled
      against mysqlnd a default socket can be set through the <link linkend="ini.pdo-mysql.default-socket">
      pdo_mysql.default_socket</link> setting.
     </para>
    </note>
   </refsect1>
  </refentry>

 </reference>

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