New in 10: Compile-Time Warnings

This will allow you to improve code before it runs live.

"ALTER SESSION" is recommended, as "ALTER SYSTEM" takes too much overhead, or use "ALTER PROCEDURE ... COMPILE."

Find message descriptions by SHOW ERRORS or query User_Errors (PLW-)

Category	Msg #s	Example
Severe	5000-5999	Aliasing problems with parameters
Informational	6000-6249	Code that can never run
Performance	7000-7249	Passing a VARCHAR2 value to a NUMBER column

value_clause::=
{ ENABLE | DISABLE | ERROR* }:
{ All| Severe| Informational| Performance|
{ Integer| (Integer [, Integer ] ...)}}
* 'Error' treats a particular message as an error instead of a warning.

Examples:

Alter Session Set Plsql_Warnings = 
               'Enable:Severe', 'Disable:Informational';
Alter Session Set Plsql_Warnings = 
               'Disable:All';
Alter Session Set Plsql_Warnings = 
               'Disable:5000', 'Enable:5001','Error:5002';
Alter Session Set Plsql_Warnings = 
               'Enable:(5000,5001,5002)','Disable:6000,6001)';
Alter Procedure prog_x Compile Plsql_Warnings=
               'Enable:Performance';
Call Dbms_Warning.Set_Warning_Setting_String
               ('Enable:All' ,'Session');

To see how it's currently set:

BEGIN
DBMS_OUTPUT.PUT_LINE('$$PLSQL_WARNINGS = ' || $$PLSQL_WARNINGS);
END;
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