On Mon, Dec 20, 2004 at 09:56:35AM +0200, Vitaly Belman wrote: > I have two tables. "Books" and "Book_Authors" (which links between > book_id and author_id).
Is there a third table, perhaps Authors? > Book_authors has a foreign key on book_id to the Books table. On key > violation it is set to delete the rows (if a book is deleted, it > should't be linked to any authors). > > In Book_Authors I also have a trigger on DELETE. When a book is > unlinked from an author, then the author vote_count should be reduced > (as the author vote_count is the sum of all votes of his books). Which table has vote_count -- the Authors table that I'm guessing exists? Where does vote_count's value come from? A field in Books? Is there a reason you're maintaining vote_count instead of querying for it with an aggregate like SUM or COUNT? > The problem is that when a book is deleted and then the trigger tried > to get the number of it votes, it returns NULL, as the book is already > gone and so its data. If it was a simple matter of triggers I could > play with BEFORE/AFTER, but since it is constraints issue, it seems to > be all happening AFTER the deletion. Is there a reason you can't maintain vote_count with a trigger on Books? Could you post a minimal but complete example (CREATE statements and INSERT or COPY statements with sample data) so we can get a better idea of what you're trying to do? -- Michael Fuhr http://www.fuhr.org/~mfuhr/ ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
