(PHP 5, PHP 7) Changes the user of the specified database connection

(PHP 5 >= 5.5.0, PHP 7) Starts a transaction

(PHP 5, PHP 7) Returns the MySQL client version as an integer

(PHP 5, PHP 7) Pings a server connection, or tries to reconnect if the connection has gone down

(PHP 5, PHP 7) Returns the version of the MySQL server

(PHP 5, PHP 7) Turns on or off auto-committing database modifications

(PHP 5 >= 5.0.5, PHP 7) Sets the default client character set

(PHP 5, PHP 7) Selects the default database for database queries

(PHP 5, PHP 7) Gets the number of affected rows in a previous MySQL operation

(PHP 5, PHP 7) Returns the version of the MySQL protocol used