NULL values in Unique constrain

From: Diego Dal Cero <diegodalcero_at_yahoo.es>
Date: 3 Oct 2001 01:50:47 -0700
Message-ID: <160d056.0110030050.7b360e43@posting.google.com>

Hi everybody,

I'm having some problem defining a table, having in mind first of all database indipendence.

My table is in his fundamentals somethink like that:

create table mytable (

   value1 integer not null,
   value2 integer null
   value3 integer not null,
   unique (value1, value2, value3)
)

Is this correct or the "value2" column should be also "not null"? In my application, in certain cases, the "value2" could be null.

Thank you very much for your help.

Diego Dal Cero. Received on Wed Oct 03 2001 - 03:50:47 CDT