On 7/7/06, operationsengineer1@yahoo.com <operationsengineer1@yahoo.com> wrote:
> i agree. all my primary keys are abstract - even
> though some don't have to be. iow, i'm comfortable
> using serials as my primary key even when i don't
> absolutely need to.
Yes I had in fact already created my table using a serial as the
primary key but I've been reading Celko's SQL Programming Style and
the use of a hash on the address column as the primary key (and for
use in FK's) meets a number of the requirements for a good key. The
address column itself is the natural primary key but it doesn't make
for a good FK. Plus I feel I would be remiss in not exploring an
alternative to the serial key.
To recap, yes there is only a single column, yes it is varchar. I need
to do a lookup on the address column which is unique and use it as a
foreign key in other tables. Using a serial id would obviously work
and has been recommended. But having a hash function over the address
column as the primary key means I can always regenerate my primary key
from the data which is impossible with a serial key. I believe the
risk of collision using md5 is effectively zero on this data and I can
put a unique index over it.
I'm kind of new to sql so apologies if this is a naive approach.
Thanks to all for responses.
Dave