Hey All, I have a table, let's call it A, whose primary key, a_id, is referenced in a second table, let's call it B. For each unique A.a_id there are generally many rows in B with the same a_id. My problem is that I want to delete a row in A when the last row in B that references it is deleted. Right now I just query for rows in A that aren't referenced by B, and that worked great when the tables were small, but it takes over an hour now that the tables have grown larger (over 200 million rows in B and 14 million in A). The delete has to do a sequential scan of both tables since I'm looking for what's not in the indexes. I was going to try creating a trigger after delete on B for each row to check for more rows in B with the same a_id, and delete the row in A if none found. In general I will be deleting 10's of millions of rows from B and 100's of thousands of rows from A on a daily basis. What do you think? Does anyone have any other suggestions on different ways to approach this? Thanks, Ed
