Re: Trigger syntax

Chris wrote:

> (Oracle 7.3.4 for NT)
>
> I have two tables tab1 and tab2.
>
> What I want to be able to do is create a database trigger that
> increments a sequence in tab1 when a row is inserted in tab2 but only
> were there is currently no value in tab1. (There is a one to many
> relationship between tab1 and tab2).
>
> I can do it easily if I only had one table with something like:
>
> create or replace trigger foo_tg
> before insert on tab1
> for each row
> begin
> select foo_seq.nextval into :new.field from dual;
> end;
>
> but I'm stuck - not even sure if I'm going the right way about
> achieving what I need.
>
> Any advice would be greatly appreciated.
>
> regards
>
> Chris

I'd do an after insert trigger on table one that does a SELECT COUNT(1) on table2. If a non-zero value is returned ... insert.

Daniel A. Morgan Received on Thu Aug 02 2001 - 14:04:52 CDT