Re: unsigned types

On Oct 16, 2005, at 5:42 , jeff sacksteder wrote:

> It occurs to me that I don't know how to define unsigned integer
> datatypes. I'm making a schema to describe network packets and I
> need columns to contain values from 0-255, etc.
>
> I can't seem to find any documentation on this. What's the best
> prectice for this situation?

PostgreSQL does not have native unsigned integer datatypes. (For
reasons why, check the archives.) You can use domains or check
constraints to enforce a non-negative constraint. For example:

create table foo (
foo_id serial not null unique
, foo_unsigned_int integer not null check (foo_unsigned_int > 0)
);

or

create created domain unsigned_integer
as integer
check (value > 0);

create table bar (
bar_id serial not null unique
, bar_unsigned_int unsigned_integer not null
);

Here are doc references:
[check constraints](http://www.postgresql.org/docs/8.0/interactive/
ddl-constraints.html#AEN1936)
[create domain](http://www.postgresql.org/docs/8.0/interactive/sql-
createdomain.html)

Hope this helps.

Michael Glaesemann
grzm myrealbox com