# MySQL PDO Driver (PDO_MYSQL)

## Introduction

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

PDO_MYSQL uses emulated prepares by default.

MySQL 8

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 is fully supported as of PHP 7.4.4. For older releases, the mysql_xdevapi extension does support it.

Warning

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.

> Note:

> The MySQL driver does not properly support `PDO::PARAM_INPUT_OUTPUT` via PDOStatement::bindParam(); while such parameters can be used, they are not updated (i.e. the actual output is ignored).

## Installation

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 that 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. 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::ATTR_SSL_*`, 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.

## Predefined Constants

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.

`PDO::MYSQL_ATTR_USE_BUFFERED_QUERY` (int)
  Alias of `Pdo\Mysql::ATTR_USE_BUFFERED_QUERY`
`PDO::MYSQL_ATTR_LOCAL_INFILE` (int)
  Alias of `Pdo\Mysql::ATTR_LOCAL_INFILE`
`PDO::MYSQL_ATTR_LOCAL_INFILE_DIRECTORY` (int)
  Alias of `Pdo\Mysql::ATTR_LOCAL_INFILE_DIRECTORY`. Available as of PHP 8.1.0.
`PDO::MYSQL_ATTR_INIT_COMMAND` (int)
  Alias of `Pdo\Mysql::ATTR_INIT_COMMAND`
`PDO::MYSQL_ATTR_READ_DEFAULT_FILE` (int)
  Alias of `Pdo\Mysql::ATTR_READ_DEFAULT_FILE`
`PDO::MYSQL_ATTR_READ_DEFAULT_GROUP` (int)
  Alias of `Pdo\Mysql::ATTR_READ_DEFAULT_GROUP`
`PDO::MYSQL_ATTR_MAX_BUFFER_SIZE` (int)
  Alias of `Pdo\Mysql::ATTR_MAX_BUFFER_SIZE`
`PDO::MYSQL_ATTR_DIRECT_QUERY` (int)
  Alias of `PDO::ATTR_EMULATE_PREPARES`
`PDO::MYSQL_ATTR_FOUND_ROWS` (int)
  Alias of `Pdo\Mysql::ATTR_FOUND_ROWS`
`PDO::MYSQL_ATTR_IGNORE_SPACE` (int)
  Alias of `Pdo\Mysql::ATTR_IGNORE_SPACE`
`PDO::MYSQL_ATTR_COMPRESS` (int)
  Alias of `Pdo\Mysql::ATTR_COMPRESS`
`PDO::MYSQL_ATTR_SERVER_PUBLIC_KEY` (int)
  Alias of `Pdo\Mysql::ATTR_SERVER_PUBLIC_KEY`
`PDO::MYSQL_ATTR_SSL_CA` (int)
  Alias of `Pdo\Mysql::ATTR_SSL_CA`
`PDO::MYSQL_ATTR_SSL_CAPATH` (int)
  Alias of `Pdo\Mysql::ATTR_SSL_CAPATH`
`PDO::MYSQL_ATTR_SSL_CERT` (int)
  Alias of `Pdo\Mysql::ATTR_SSL_CERT`
`PDO::MYSQL_ATTR_SSL_CIPHER` (int)
  Alias of `Pdo\Mysql::ATTR_SSL_CIPHER`
`PDO::MYSQL_ATTR_SSL_KEY` (int)
  Alias of `Pdo\Mysql::ATTR_SSL_KEY`
`PDO::MYSQL_ATTR_SSL_VERIFY_SERVER_CERT` (int)
  Alias of `Pdo\Mysql::ATTR_SSL_VERIFY_SERVER_CERT` Available as of PHP 7.0.18 and PHP 7.1.4.
`PDO::MYSQL_ATTR_MULTI_STATEMENTS` (int)
  Alias of `Pdo\Mysql::ATTR_MULTI_STATEMENTS`

## Runtime Configuration

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

PDO_MYSQL Configuration Options
Name | Default | Changeable
--- | --- | ---
pdo_mysql.default_socket | "/tmp/mysql.sock" | `INI_SYSTEM`
pdo_mysql.debug | NULL | `INI_SYSTEM`

For further details and definitions of the INI_* modes, see the Where a configuration setting may be set.

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` bool

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

## Table of Contents

- PDO_MYSQL DSN — Connecting to MySQL databases

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