# MySQL Functions (PDO_MYSQL)

## Introduction

PDO_MYSQL is a driver that implements the PHP Data Objects (PDO) interface to enable access from PHP to MySQL 3.x, 4.x and 5.x 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.

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.

## 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 mysql-specific attributes with the postgres 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` (integer)
  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#1 Forcing queries to be buffered in mysql

  `<?php
  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");
  }
  ?>`
`PDO::MYSQL_ATTR_LOCAL_INFILE` (integer)

  Enable LOAD LOCAL INFILE.

`PDO::MYSQL_ATTR_INIT_COMMAND` (integer)

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

`PDO::MYSQL_ATTR_READ_DEFAULT_FILE` (integer)

  Read options from the named option file instead of from my.cnf.

`PDO::MYSQL_ATTR_READ_DEFAULT_GROUP` (integer)

  Read options from the named group from my.cnf or the file specified with `MYSQL_READ_DEFAULT_FILE`.

`PDO::MYSQL_ATTR_MAX_BUFFER_SIZE` (integer)

  Maximum buffer size. Defaults to 1 MiB.

`PDO::MYSQL_ATTR_DIRECT_QUERY` (integer)

  Perform direct queries, don't use prepared statements.