Re: Create unique field..

One other thing you need to do is to make sure that
you don't actually put some other information into
that column. For example, let's say that you have a
table defined like this:

processdata=# create sequence foo_seq;
CREATE
processdata=# create table foo (id int default
nextval('foo_seq'), name text);
CREATE

You might want to get a little fancier and make id a
primary key or something, but this gives you the
general idea.

Now if you were to insert a record where id was set
then your default value would get overwritten:

processdata=# insert into foo (id, name) values (100,
'Jason');
INSERT 6869711 1
processdata=# insert into foo (name) values ('Earl');
INSERT 6869712 1
processdata=# select * from foo
processdata-# ;
id | name
-----+-------
100 | Jason
1 | Earl
(2 rows)

You will notice that the insert that I did where I did
not set id used the sequence without any problems.
This is useful for cases where you *normally* want to
use the sequence but where there might be exceptions.

Hope this is helpful,

Jason

--- "Williams, Travis L, NPONS" <tlw(at)att(dot)com> wrote:
> All,
> I'm not sure if I'm on the right track here.. I
> want to create a
> column that is automatically filled in with a unique
> number when a row is
> created.. I thought that creating a sequence would
> do this.. and then
> creating a column with a default of
> nextval('seqname') but it isn't doing
> anything.. any help is appreciated...
>
> Thanks,
> Travis L. Williams
>
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