Dublicates pairs in a table.
От | Ries van Twisk |
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Тема | Dublicates pairs in a table. |
Дата | |
Msg-id | 000201c25d90$87230c10$6500000a@IT000 обсуждение исходный текст |
Ответы |
Re: Dublicates pairs in a table.
|
Список | pgsql-sql |
Dear guys/girls, I have a small question which I could not clearly find in the postgreSQL manual. if I create this table and index CRAEATE TABLE test (id SERIAL,c1 VARCHAR(32),c2 VARCHAR(32),c3 VARCHAR(32) ); CREATE UNIQUE INDEX test_idx ON test(id, c1,c2); what I try to archive here is that I don't want duplicate pais in my table: example INSET INTO test (c1,c2) VALUES('a', 'a'); -- Allowed INSET INTO test (c1,c2) VALUES('b', 'b'); -- Allowed INSET INTO test (c1,c2) VALUES('b', 'c'); -- Allowed INSET INTO test (c1,c2) VALUES('a', 'a'); -- Not allowed since we already have a duplicate ('a', 'a') pair INSET INTO test (c1,c2) VALUES('b', 'c'); -- Not allowed since we already have a duplicate ('b', 'c') pair etc. etc. I think you get the idea... What I want to know is that if this is smart do do, or is there a other better way to make sure I don't insert duplicate pairs in my database. I'm not sure if a stored procedure is better in my case since I don't really need the index on columns c1 or c2. I'm looking for performance technical answers here thus speed vs memory comparisons. Ofcourse a pointer to a URL will also do.. Best Regards, Ries van Twisk
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