Serial / auto increment data type

On Wed, 2005-04-27 at 15:43, Typing80wpm@aol.com wrote:

I am just beginning to teach myself Postgresql and Access. I notice
that PG has the "serial" type of field which increments
automatically. I notice that when I do external links in Access
through ODBC, that Access wants a field or fields which will be
unique.

Here is my question. Would I be wise to define each and ever table
with a serial id, so that I may always be guaranteed something uniqe,
to satisfy Access. It seems to me like no harm can be done, since if
you dont need the serial id, you dont need it, but it is always there
if you do need it, and it is harder to add such a field down the line,
after the fact.

Since 7.4 or 7.3 (I forget which) serial has NOT guaranteed uniqueness.
you have to add unique or primary key to the declaration like so:

create table foo (bar serial unique, otherfield int);

Or replace "unique" with "primary key"...

Yes, that is the way to do it.

I migrated several large Access DB to postgres and most of the tables that where done by the
non developers didn't have a primary key defined, so the easiest way was just to add a new field to every table and make it a serial.

I believe you would have to do this even if you were using MS SQL server as the backend.

Here is my question. Would I be wise to define each and ever table with
a serial id, so that I may always be guaranteed something uniqe, to
satisfy Access. It seems to me like no harm can be done, since if you
dont need the serial id, you dont need it, but it is always there if you
do need it, and it is harder to add such a field down the line, after
the fact.

Thanks!

--
Tony Caduto
AM Software Design
Home of PG Lightning Admin for Postgresql 8.x
http://www.amsoftwaredesign.com