USER DEFINED EXCEPTIONS

         Apart from sytsem exceptions we can explicitly define exceptions based on business rules.These are known as user defined exceptions.

*They should be explicitly declared in the declaration section.

*They should be explicitly raised in the execution section,

*They should be handled by referencing the user defined exception name in the exception section.

Example:

Declare

praveen Exception;

a number:=&a;

begin

if(a>0) then

dbms_output.put_line('a is positive');

else

if(a=0) then

raise praveen;

else 

dbms_output.put_line('a is negative');

end if;

end if;

Exception

when praveen then

dbms_output.put_line('a is neutral');

end;