Chapter 4 MySQL Functions (PDO_MYSQL)

Table of Contents


Copyright 1997-2018 the PHP Documentation Group.

PDO_MYSQL is a driver that implements the PHP Data Objects (PDO) interface to enable access from PHP to MySQL databases.

PDO_MYSQL will take advantage of native prepared statement support present in MySQL 4.1 and higher. If you're using an older version of the mysql client libraries, PDO will emulate them for you.


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 mysql_native_password or else you will see errors similar to The server requested authentication method unknown to the client [caching_sha2_password] even when caching_sha2_password is not used.

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 default_authentication_plugin=mysql_native_password in my.cnf. The caching_sha2_password plugin will be supported in a future PHP release. In the meantime, the mysql_xdevapi extension does support it.


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.

The common Unix distributions include binary versions of PHP that can be installed. Although these binary versions are typically built with support for the MySQL extensions, the extension libraries themselves may need to be installed using an additional package. Check the package manager than comes with your chosen distribution for availability.

For example, on Ubuntu the php5-mysql package installs the ext/mysql, ext/mysqli, and PDO_MYSQL PHP extensions. On CentOS, the php-mysql package also installs these three PHP extensions.

Alternatively, you can compile this extension yourself. Building PHP from source allows you to specify the MySQL extensions you want to use, as well as your choice of client library for each extension.

When compiling, use --with-pdo-mysql[=DIR] to install the PDO MySQL extension, where the optional [=DIR] is the MySQL base library. As of PHP 5.4, mysqlnd is the default library. For details about choosing a library, see Choosing a MySQL library.

Optionally, the --with-mysql-sock[=DIR] sets to location to the MySQL unix socket pointer for all MySQL extensions, including PDO_MYSQL. If unspecified, the default locations are searched.

Optionally, the --with-zlib-dir[=DIR] is used to set the path to the libz install prefix.

$ ./configure --with-pdo-mysql --with-mysql-sock=/var/mysql/mysql.sock


SSL support is enabled using the appropriate PDO_MySQL constants, which is equivalent to calling the MySQL C API function mysql_ssl_set(). Also, SSL cannot be enabled with PDO::setAttribute because the connection already exists. See also the MySQL documentation about connecting to MySQL with SSL.

Table 4.1 Changelog

5.4.0mysqlnd became the default MySQL library when compiling PDO_MYSQL. Previously, libmysqlclient was the default MySQL library.
5.4.0MySQL client libraries 4.1 and below are no longer supported.
5.3.9Added SSL support with mysqlnd and OpenSSL.
5.3.7Added SSL support with libmysqlclient and OpenSSL.

The constants below are defined by this driver, and will only be available when the extension has been either compiled into PHP or dynamically loaded at runtime. In addition, these driver-specific constants should only be used if you are using this driver. Using driver-specific attributes with another driver may result in unexpected behaviour. PDO::getAttribute may be used to obtain the PDO::ATTR_DRIVER_NAME attribute to check the driver, if your code can run against multiple drivers.


If this attribute is set to TRUE on a PDOStatement, the MySQL driver will use the buffered versions of the MySQL API. If you're writing portable code, you should use PDOStatement::fetchAll instead.

Example 4.1 Forcing queries to be buffered in mysql

if ($db->getAttribute(PDO::ATTR_DRIVER_NAME) == 'mysql') {
    $stmt = $db->prepare('select * from foo',
        array(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => true));
} else {
    die("my application only works with mysql; I should use \$stmt->fetchAll() instead");



Note, this constant can only be used in the driver_options array when constructing a new database handle.


Command to execute when connecting to the MySQL server. Will automatically be re-executed when reconnecting.

Note, this constant can only be used in the driver_options array when constructing a new database handle.


Read options from the named option file instead of from my.cnf. This option is not available if mysqlnd is used, because mysqlnd does not read the mysql configuration files.


Read options from the named group from my.cnf or the file specified with MYSQL_READ_DEFAULT_FILE. This option is not available if mysqlnd is used, because mysqlnd does not read the mysql configuration files.


Maximum buffer size. Defaults to 1 MiB. This constant is not supported when compiled against mysqlnd.


Perform direct queries, don't use prepared statements.


Return the number of found (matched) rows, not the number of changed rows.


Permit spaces after function names. Makes all functions names reserved words.


Enable network communication compression. This is also supported when compiled against mysqlnd as of PHP 5.3.11.


The file path to the SSL certificate authority.

This exists as of PHP 5.3.7.


The file path to the directory that contains the trusted SSL CA certificates, which are stored in PEM format.

This exists as of PHP 5.3.7.


The file path to the SSL certificate.

This exists as of PHP 5.3.7.


A list of one or more permissible ciphers to use for SSL encryption, in a format understood by OpenSSL. For example: DHE-RSA-AES256-SHA:AES128-SHA

This exists as of PHP 5.3.7.


The file path to the SSL key.

This exists as of PHP 5.3.7.


Disables multi query execution in both PDO::prepare and PDO::query when set to FALSE.

Note, this constant can only be used in the driver_options array when constructing a new database handle.

This exists as of PHP 5.5.21 and PHP 5.6.5.

The behaviour of these functions is affected by settings in php.ini.

Table 4.2 PDO_MYSQL Configuration Options


For further details and definitions of the PHP_INI_* modes, see the

Here's a short explanation of the configuration directives.

pdo_mysql.default_socket string

Sets a Unix domain socket. This value can either be set at compile time if a domain socket is found at configure. This ini setting is Unix only.

pdo_mysql.debug boolean

Enables debugging for PDO_MYSQL. This setting is only available when PDO_MYSQL is compiled against mysqlnd and in PDO debug mode.


Copyright 1997-2018 the PHP Documentation Group.


    Connecting to MySQL databases


The PDO_MYSQL Data Source Name (DSN) is composed of the following elements:

DSN prefix

The DSN prefix is mysql:.


The hostname on which the database server resides.


The port number where the database server is listening.


The name of the database.


The MySQL Unix socket (shouldn't be used with host or port).


The character set. See the character set concepts documentation for more information.

Prior to PHP 5.3.6, this element was silently ignored. The same behaviour can be partly replicated with the PDO::MYSQL_ATTR_INIT_COMMAND driver option, as the following example shows.


The method in the below example can only be used with character sets that share the same lower 7 bit representation as ASCII, such as ISO-8859-1 and UTF-8. Users using character sets that have different representations (such as UTF-16 or Big5) must use the charset option provided in PHP 5.3.6 and later versions.

Example 4.2 Setting the connection character set to UTF-8 prior to PHP 5.3.6

$dsn = 'mysql:host=localhost;dbname=testdb';
$username = 'username';
$password = 'password';
$options = array(

$dbh = new PDO($dsn, $username, $password, $options);


5.3.6Prior to version 5.3.6, charset was ignored.


Example 4.3 PDO_MYSQL DSN examples

The following example shows a PDO_MYSQL DSN for connecting to MySQL databases:



More complete examples:




Unix only:

When the host name is set to "localhost", then the connection to the server is made thru 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 thru the pdo_mysql.default_socket setting.