RE: Delete Trigger Issue

Let me make sure I get this right:

CREATE TABLE table1( field1 varchar(64),   ... );

CREATE TABLE table2( field2 varchar(64),  ... );

and you want that whenever a row is deleted from table1
you want the SAME row to be deleted from table2?

here's what you want. First, a trigger:

CREATE TRIGGER update_table2
BEFORE DELETE
ON table1
FOR EACH ROW
EXECUTE PROCEDURE update_table2_proc();

That trigger will make sure that each time a row is deleted
from table1, the proceudre update_table2_proc will
be called. And here is that procedure

CREATE FUNCTION update_table2_proc()
RETURNS opaque
AS
'BEGIN  DELETE FROM table2 WHERE field2 = new.field1;  RETURN new;END;'
LANGUAGE 'plpgsql';

That procedure just DELETEs all the rows in table2
that match up to field1 in the first table.
Of course, you might want to do a broader
LIKE matching if they are really VARCHAR fields.

Hope that helps!

-Robby Slaughter



-----Original Message-----
From: pgsql-sql-owner@postgresql.org
[mailto:pgsql-sql-owner@postgresql.org]On Behalf Of Sundararajan
Sent: Tuesday, August 07, 2001 12:16 AM
To: pgsql-sql@postgresql.org
Subject: [SQL] Delete Trigger Issue


I am developing a db application in postgresql and i need to write a delete
trigger on one of the tables.

the environment is

table1

field1 varchar(64)
other fields.

table 2.

field1 varchar(64)
other fields

I need a delete trigger on the table 1, so that if I delete a row from table
1 , the corresponding rows from table 2 should also be deleted.

This is the code I have tried.

DROP FUNCTION ApplicationsDeleteFn();
CREATE FUNCTION ApplicationsDeleteFn()
RETURNS OPAQUE
AS 'BEGIN
delete from ports where appName=OLD.appName;RETURN OLD;
END;
'
LANGUAGE 'plpgsql';

Please help me with this, as my work is time bound.Even if the trigger is
written is SQL

Thanks
sundar


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