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

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

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

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

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

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

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

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

(PHP 5, PHP 7) Prepare an SQL statement for execution

(PHP 5, PHP 7) Returns a string representing the type of connection used