Re: Are these two creation commands functionally identical?
От | Ragnar |
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Тема | Re: Are these two creation commands functionally identical? |
Дата | |
Msg-id | 1186824078.528.19.camel@localhost.localdomain обсуждение исходный текст |
Ответ на | Are these two creation commands functionally identical? (dterrors@hotmail.com) |
Ответы |
Re: Are these two creation commands functionally identical?
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Список | pgsql-general |
On fim, 2007-08-09 at 20:55 +0000, dterrors@hotmail.com wrote: > I want to to know if these two are functionally equivalent. Is this: > > Create table "sales" > ( > "saleid" BigSerial NOT NULL, > "userid" Bigint NOT NULL, > "parent_saleid" Bigint NOT NULL, > primary key ("saleid") > ) Without Oids; > Alter table "sales" add foreign key ("userid") references > "users" ("userid") on update restrict on delete restrict; > Alter table "sales" add foreign key ("parent_saleid") references > "sales" ("saleid") on update restrict on delete restrict; this constraint seems a bit strange to me. are you going to special-case the first insert into this table? > Is the above functionally identical to: > > Create table "sales" > ( > "saleid" BigSerial NOT NULL, > "userid" bigint references users(userid), > "parent_saleid" bigint references sales(saleid), > primary key ("saleid") > ) Without Oids; no these 2 are not fuctionally identical, because the second one does not have a NOT NULL constraint on the foreign keys, allowing you to insert: INSERT INTO sales (saleid,userid,parent_saleid) VALUES (100,null,100); gnari
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