Re: FK question
От | Martijn van Oosterhout |
---|---|
Тема | Re: FK question |
Дата | |
Msg-id | 20040828002515.GA9819@svana.org обсуждение исходный текст |
Ответ на | FK question ("Igor Kryltsov" <kryltsov@yahoo.com>) |
Список | pgsql-general |
The second will allow combinations of (survey_id,employee_id) that are not in employee_survey as long as the individual survey_id and employee_id's exist. Whether that's a problem or not depends on your schema.... On Thu, Aug 26, 2004 at 04:48:12PM +1000, Igor Kryltsov wrote: > Hi, > > What is a difference, if any, between: > _________________________________ > ALTER TABLE ONLY employee_role > ADD CONSTRAINT fk_survey_id_employee_id FOREIGN KEY (survey_id, > employee_id) REFERENCES employee_survey(survey_id, employee_id) MATCH FULL > ON UPDATE C > ASCADE ON DELETE CASCADE; > __________________________________ > > AND > ___________________________________ > ALTER TABLE ONLY employee_role > ADD CONSTRAINT fk_survey_id FOREIGN KEY (survey_id) REFERENCES > employee_survey(survey_id) MATCH FULL ON UPDATE C > ASCADE ON DELETE CASCADE; > > ALTER TABLE ONLY employee_role > ADD CONSTRAINT fk_employee_id FOREIGN KEY (employee_id) REFERENCES > employee_survey(employee_id) MATCH FULL ON UPDATE C > ASCADE ON DELETE CASCADE; > _____________________________________ > > > Thank you, > > > Igor > > > > ---------------------------(end of broadcast)--------------------------- > TIP 2: you can get off all lists at once with the unregister command > (send "unregister YourEmailAddressHere" to majordomo@postgresql.org) -- Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/ > Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a > tool for doing 5% of the work and then sitting around waiting for someone > else to do the other 95% so you can sue them.
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