Using Pragma RESTRICT_REFERENCES:

The function called from the SQL statements should obey certain rules meant to control the side effects. To check for violation of the rules, you can use the RESTRICT_REFERENCES pragma that instructs the compiler to report reads and/or writes to database tables and/or package variables.

Avoiding Deadlocks

In some situations when executing a SQL data definition statement, the outcome is a deadlock.

For illustration, the procedure below causes a deadlock as it attempts to drop itself. To avoid the deadlocks, never try to ALTER or DROP a subprogram or package while you are still using it.

CREATE PROCEDURE calc_bonus (emp_id NUMBER) AS

BEGIN

...

EXECUTE IMMEDIATE 'DROP PROCEDURE calc_bonus';

-- causes "timeout occur while waiting to the lock object" error

END;