Help with Database Trigger

From: SH Chua <shchua_at_technet.sg>
Date: 1995/06/04
Message-ID: <3qrhla$123_at_raffles.technet.sg>#1/1


I want to create a database trigger to validate the values of some fields whenever there's any insert/update on table.

Example :

Table1 has 3 fields :

field1  varchar2(5)
field2  varchar2(5)
field3  varchar2(5)

The trigger I tried to create is as follows :

create trigger
after insert or update on table1
begin

      if field1 is null
      then
          if field2 is not in ('A', 'B', 'C')
          then raise_application_err( .........);
          end if;
     else
          if field2 is null or field3 is not in ('X', 'Y')
          then raise_application_error(.............);
     end if;

end;

When I tried to create the above trigger, I received error message saying
"field1" is not declared!
"field1" is actually from the table TABLE1; why must I declare the field?
How can I write the above trigger to validate the values of the field before user commits the record into the table?
Prompt reply is appreciated. Received on Sun Jun 04 1995 - 00:00:00 CEST

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