SET option '=' scalar_exp
| SET option OFF
| SET option ON
The SET statement sets an option to a value. Options may control
trigger invocation, transaction isolation and other settable
parameters of the engine. A SET inside a procedure takes effect
inside the procedure and invoked procedures, counting from time of
execution. Control must pass through the SET statement for it to
take effect, i.e. SET is not a declaration. The effect of a SET
does typically not persist across procedure return.
A SET given at top level, i.e. directly executed and by a client
as the statement of a SQLExecute sets an option at the connection
level. This may only be reversed by another SET.