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@att.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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