(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) Returns the MySQL client version as an integer

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

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

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

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

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

(PHP 5 >= 5.5.0, PHP 7) Set a named transaction savepoint

(PHP 5 >= 5.4.0, PHP 7) Returns a list of errors from the last command executed