Re: Unique primary index?
| От | PFC |
|---|---|
| Тема | Re: Unique primary index? |
| Дата | |
| Msg-id | op.ss3av5both1vuj@localhost обсуждение исходный текст |
| Ответ на | Unique primary index? (orange_crush_068@hotmail.com) |
| Ответы |
Re: Unique primary index?
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| Список | pgsql-sql |
index is... an index ! UNIQUE is an index which won't allow duplicate values (except for NULLS) PRIMARY KEY is exactly like UNIQUE NOT NULL, with the bonus that the database knows this column is the primary key so you can use stuff like NATURAL JOIN without telling which column you want to use. > > What are the major differences between Unique, primary index & just > plain index? > > When creating tables I nominate one of these, but not sure what the > difference is? > > > ---------------------------(end of broadcast)--------------------------- > TIP 8: explain analyze is your friend >
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