* Zbigniew Lukasiak <[EMAIL PROTECTED]> [2007-02-02 13:25]: > select * from a, b, c where > a.key1 = b.key2 and b.key1 = c.key2 and c.key1 = a.key2 > > With composed (key1, key2) primary keys for a, b and c tables. > > This join is a three table relationship (just like the many to > many case) - and I think it is not reducible to a superposition > of two table relstionships (differently from the many to many > case).
Heh. And unless you weaken your FK constraints, you will never be able to insert a row into these tables. :P (Except maybe with some kind of multiple-table insert support, using a view or whatever.) > To reiterate - I did read your thesis that many to many is not > a relatioship - so you don't need to repeat that - I am just > asking why it is not and what is a relatioship. I think a relationship is anything you can say in SQL DDL. Regards, -- Aristotle Pagaltzis // <http://plasmasturm.org/> _______________________________________________ List: http://lists.rawmode.org/cgi-bin/mailman/listinfo/dbix-class Wiki: http://dbix-class.shadowcatsystems.co.uk/ IRC: irc.perl.org#dbix-class SVN: http://dev.catalyst.perl.org/repos/bast/trunk/DBIx-Class/ Searchable Archive: http://www.mail-archive.com/[email protected]/
