Re: foreign keys constraints, depending on each other
От | zilch@home.se |
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Тема | Re: foreign keys constraints, depending on each other |
Дата | |
Msg-id | 20010610234017.A29638@loony обсуждение исходный текст |
Ответ на | Re: foreign keys constraints, depending on each other (Stephan Szabo <sszabo@megazone23.bigpanda.com>) |
Ответы |
Re: foreign keys constraints, depending on each other
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Список | pgsql-general |
> > I was just creating this little database for demonstrating the use of > > foreign keys constraints. > > > > I was about the create 3 tables, namely mother, father and child. Mother has > > a foreign key pointing at father ( id ), and father has a foreign key > > pointing at mother ( id ). Child has one pointer to mother ( id ) and one > > pointer to father ( id ). How can I prevent the error message from occurring? > > You don't put the constraint at table creation time. The table referenced > by the references has to exist. Use ALTER TABLE to add the constraint > after creating table father. > I tried: BEGIN; SET CONSTRAINTS ALL DEFERRED; INSERT INTO mother (fatherID, name) VALUES ( 1, 'mamma' ) ; INSERT INTO father (motherID, name) VALUES ( 1, 'pappa' ) ; INSERT INTO child (motherID, fatherID, name) VALUES (1, 1, 'barn 1') ; INSERT INTO child (motherID, fatherID, name) VALUES (1, 1, 'barn 2') ; COMMIT; ...which did not work. Still it complains about key referenced from mother not found in father. --- Daniel Akerud
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