START TRANSACTION [ ISOLATION LEVEL { READ COMMITTED | SERIALIZABLE } ] [ READ WRITE | READ ONLY ]
This command begins a new transaction. If the isolation level or read/write mode is specified, the new transaction has those characteristics, as if SET TRANSACTION [set_transaction(7)] was executed. In all other respects, the behavior of this command is identical to the BEGIN [begin(7)] command.
See under SET TRANSACTION [set_transaction(7)] about the meaning of the parameters.
This command conforms to the SQL standard; but see also the compatibility section of SET TRANSACTION [set_transaction(7)].