PDO_MYSQL is a driver that implements the PHP Data Objects (PDO) interface to enable access from PHP to MySQL 3.x and 4.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.
Beware: MySQL tables do not support transactions by default. When writing transactional database code, MySQL will pretend that a transaction was initiated successfully, even when no transactional support is present. In addition, any DDL queries issued will implicitly commit any pending transactions.
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.
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.
Пример 1. Forcing queries to be buffered in mysql