Re: need help for triggers

Venkat Mundrathi schrieb:
>
> I am new to oracle(triggers). I am using personal oracle 8.0,
>
> 1)The purpose of trigger is when ever I insert a new row in the emp
> table(hope you know the description) with the same empno or ename it has to
> fire and give an error message to user that the row with empno or ename is
> already exist.

create or replace trigger tbi_emp before insert on emp for each row declare l_counter number;
begin

	   select 
	   	  count(empno)
		into
		  l_counter
		from
		  emp
		where
		  empno=:new.empno
		and
		  rowid!=:new.rowid;
		if l_counter!=0 then
		   RAISE_APPLICATION_ERROR(-20000,'Got empno yet!');
		end if; 	

> 2) I created a new table U_OBJECTS( name varchar(40),type
> varchar(15),created date). I inserted the values from user_objects table.
> Now i tried to create a trigger, it should fire such that when ever a new
> row is inserted in user_objects the table U_OBJECTS has to be updated( does
> this sounds ridiculous). when i was compiling thetrigger it is give me the
> following error
>
> ORA 25001- CANNOT CREATE THIS TRIGGER TYPE ON VIEWS
user_objects is a view not a table!!

>
> can you please comment on this.
>
> thanks in advance

HTH
Matthias
--
grema_at_t-online.de

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