Re: identity columns ?

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От Joshua b. Jore
Тема Re: identity columns ?
Дата
Msg-id Pine.BSO.4.40.0204051100460.2976-100000@kitten.greentechnologist.org
обсуждение исходный текст
Ответ на Re: identity columns ?  ("Josh Berkus" <josh@agliodbs.com>)
Ответы Re: identity columns ?  (Tom Lane <tgl@sss.pgh.pa.us>)
Список pgsql-novice
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So this raises a question I was wondering, what use *is* the oid column in
non-system tables? The only thing I could think of is for last-resort row
uniqueness if the application somehow borked up. Are there any other
reasons to even have this column in a user table?

Joshua b. Jore
http://www.greentechnologist.org

On Fri, 5 Apr 2002, Josh Berkus wrote:

> Harald, Chris,
>
> > > 1. M$ SQL Server has an identity column which generates a
> >  sequential number
> > > for you, we use this often for unique primary keys. Does postgres
> >  support
> > > anything like  this ?
> >
> > select *,oid from your_table
>
> NO!!!! This is wrong.  DO NOT USE the oid for anything other than
>  system purposes.  It is NOT a user-friendly value for several reasons.
>
> Chris, the data type you want is SERIAL.  Please read the section of
>  the docs on sequences:
> http://www.postgresql.org/idocs/index.php?sql-createsequence.html
> ... as the SERIAL datatype simply automates the creation of a sequence.
>   BTW, postgres sequences are both more powerful and more user-friendly
>  than MS SQL Identity columns.
>
> I would also strongly suggest buying a beginner's postgresql book, such
>  as "PostgreSQL: Introduction and Concepts" or Wrox Press' PostgreSQL
>  book.
>
> -Josh Berkus
>
> ---------------------------(end of broadcast)---------------------------
> TIP 6: Have you searched our list archives?
>
> http://archives.postgresql.org
>
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