Re: system maintained keys

Check out the SERIAL type.  It does precisely what you
want.  An idea as to how this is used would be like
this:

CREATE TABLE foo ( prim_key     SERIAL PRIMARY KEY, bar          text
);

I tend to create sequences by hand like this:

CREATE SEQUENCE my_sequence_seq;

And then I create my table with a definition like
this:

CREATE TABLE foo ( prim_key     int DEFAULT nextval('my_sequence_seq')                PRIMARY KEY, bar          text,
);

But that's just because I have been using PostgreSQL
long enough that it didn't have the SERIAL type when I
started.  The SERIAL type is just syntactic sugar for
what I generally do the long way.

Either way you simply pretend that the column isn't
there when you do inserts (unless you know what you
are doing) like so:

INSERT INTO foo (bar) VALUES ('hello');
INSERT INTO foo (bar) VALUES ('goodbye');

And then when you select you get:

processdata=> SELECT * FROM foo;prim_key |   bar   
----------+---------       1 | hello       2 | goodbye
(2 rows)

I hope that is helpful,
Jason Earl

--- Stefan Lindner <lindner@visionet.de> wrote:
> Is there any way to get system maintained keys from
> postgres? e.g. to
> have a table with a primary key column (varchar or
> int) and let postgres
> chose the next unique value for this column?
> 
> 
> 
> ---------------------------(end of
> broadcast)---------------------------
> TIP 6: Have you searched our list archives?
> 
> http://archives.postgresql.org


__________________________________________________
Do You Yahoo!?
Make a great connection at Yahoo! Personals.
http://personals.yahoo.com