mysql-connect.xml

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<refentry xml:id="function.mysql-connect" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>mysql_connect</refname>
  <refpurpose>Open a connection to a MySQL Server</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
  <warning>
   &mysql.alternative.note;
   <simplelist role="alternatives">
    <member><function>mysqli_connect</function></member>
    <member><methodname>PDO::__construct</methodname></member>
   </simplelist>
  </warning>
 </refsynopsisdiv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type class="union"><type>resource</type><type>false</type></type><methodname>mysql_connect</methodname>
   <methodparam choice="opt"><type>string</type><parameter>server</parameter><initializer>ini_get("mysql.default_host")</initializer></methodparam>
   <methodparam choice="opt"><type>string</type><parameter>username</parameter><initializer>ini_get("mysql.default_user")</initializer></methodparam>
   <methodparam choice="opt"><type>string</type><parameter>password</parameter><initializer>ini_get("mysql.default_password")</initializer></methodparam>
   <methodparam choice="opt"><type>bool</type><parameter>new_link</parameter><initializer>&false;</initializer></methodparam>
   <methodparam choice="opt"><type>int</type><parameter>client_flags</parameter><initializer>0</initializer></methodparam>
  </methodsynopsis>
  <para>
   Opens or reuses a connection to a MySQL server. 
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>server</parameter></term>
     <listitem>
      <para>
       The MySQL server. It can also include a port number. e.g. 
       "hostname:port" or a path to a local socket e.g. ":/path/to/socket" for 
       the localhost.
      </para>
      <para>
       If the PHP directive <link linkend="ini.mysql.default-host">
       mysql.default_host</link> is undefined (default), then the default 
       value is 'localhost:3306'. In &sqlsafemode;, this parameter is ignored
       and value 'localhost:3306' is always used.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>username</parameter></term>
     <listitem>
      <para>
       The username. Default value is defined by <link
       linkend="ini.mysql.default-user">mysql.default_user</link>. In
       &sqlsafemode;, this parameter is ignored and the name of the user that
       owns the server process is used.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>password</parameter></term>
     <listitem>
      <para>
       The password. Default value is defined by <link
       linkend="ini.mysql.default-password">mysql.default_password</link>. In
       &sqlsafemode;, this parameter is ignored and empty password is used.
      </para>
     </listitem>
    </varlistentry>   
    <varlistentry>
     <term><parameter>new_link</parameter></term>
     <listitem>
      <para>
       If a second call is made to <function>mysql_connect</function>
       with the same arguments, no new link will be established, but
       instead, the link identifier of the already opened link will be
       returned. The <parameter>new_link</parameter> parameter modifies this 
       behavior and makes <function>mysql_connect</function> always open 
       a new link, even if <function>mysql_connect</function> was called 
       before with the same parameters.
       In &sqlsafemode;, this parameter is ignored.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>client_flags</parameter></term>
     <listitem>
      <para>
       The <parameter>client_flags</parameter> parameter can be a combination 
       of the following constants:
       128 (enable <literal>LOAD DATA LOCAL</literal> handling),
       <constant>MYSQL_CLIENT_SSL</constant>,
       <constant>MYSQL_CLIENT_COMPRESS</constant>, 
       <constant>MYSQL_CLIENT_IGNORE_SPACE</constant> or
       <constant>MYSQL_CLIENT_INTERACTIVE</constant>.
       Read the section about <xref linkend="mysql.client-flags" /> for further information.
       In &sqlsafemode;, this parameter is ignored.
      </para>
     </listitem>
    </varlistentry> 
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns a MySQL link identifier on success&return.falseforfailure;.
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>mysql_connect</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
    die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
?>
]]>
    </programlisting>
   </example>
  </para>
  <para>
   <example>
    <title><function>mysql_connect</function> example using <literal>hostname:port</literal> syntax</title>
    <programlisting role="php">
<![CDATA[
<?php
// we connect to example.com and port 3307
$link = mysql_connect('example.com:3307', 'mysql_user', 'mysql_password');
if (!$link) {
    die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);

// we connect to localhost at port 3307
$link = mysql_connect('127.0.0.1:3307', 'mysql_user', 'mysql_password');
if (!$link) {
    die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
?>
]]>
    </programlisting>
   </example>
  </para>
  <para>
   <example>
    <title><function>mysql_connect</function> example using  ":/path/to/socket" syntax</title>
    <programlisting role="php">
<![CDATA[
<?php
// we connect to localhost and socket e.g. /tmp/mysql.sock

// variant 1: omit localhost
$link = mysql_connect(':/tmp/mysql', 'mysql_user', 'mysql_password');
if (!$link) {
    die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);


// variant 2: with localhost
$link = mysql_connect('localhost:/tmp/mysql.sock', 'mysql_user', 'mysql_password');
if (!$link) {
    die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>

 <refsect1 role="notes">
  &reftitle.notes;
  <note>
   <para>
    Whenever you specify &quot;localhost&quot; or
    &quot;localhost:port&quot; as server, the MySQL client library will
    override this and try to connect to a local socket (named pipe on
    Windows). If you want to use TCP/IP, use &quot;127.0.0.1&quot;
    instead of &quot;localhost&quot;. If the MySQL client library tries to
    connect to the wrong local socket, you should set the correct path as
    <xref linkend="ini.mysql.default-host" /> in your PHP configuration and leave the server field
    blank.
   </para>
  </note>
  <note>
   <para>
    The link to the server will be closed as soon as the execution of
    the script ends, unless it's closed earlier by explicitly calling
    <function>mysql_close</function>.
   </para>
  </note>
  <note>
   <para>
    Error "Can't create TCP/IP socket (10106)" usually means that the <link
    linkend="ini.variables-order">variables_order</link> configure directive
    doesn't contain character <literal>E</literal>. On Windows, if the
    environment is not copied the <literal>SYSTEMROOT</literal> environment
    variable won't be available and PHP will have problems loading Winsock.
   </para>
  </note>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>mysql_pconnect</function></member>
    <member><function>mysql_close</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>

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