Is Null

Hi,
I have a silly doubt. Please tell me whether "Is Null" is a contraint
or not? If yes then why it does not show in sysconstraints view?
Regards
Arijit ChatterjeeOn May 2, 11:11 am, arijitchatterjee...@.yahoo.co.in wrote:
> Hi,
> I have a silly doubt. Please tell me whether "Is Null" is a contraint
> or not? If yes then why it does not show in sysconstraints view?
> Regards
> Arijit Chatterjee
Sorry little modification instead of "Is Null" I want to say "Not Null"|||It depends on who you ask. Technically, NOT NULL is not a constraint in SQL Server, if we by
"constraint" mean what syntax we used for other constraints, like:
ALTER TABLE ... ADD CONSTRAINT...
So, in SQL Server, NOT NULL is more like a column attribute. Of course, NOT NULL does constraint
what you are allowed to put in that column, so seen from that viewpoint, NOT NULL is a constraint.
I believe that in ANSI SQL, NOT NULL is indeed a "constraint" similar to CHECK and FOREIGN KEY,
possibly represented in the system catalog as such.
--
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://sqlblog.com/blogs/tibor_karaszi
<arijitchatterjee123@.yahoo.co.in> wrote in message
news:1178086362.445723.175660@.q75g2000hsh.googlegroups.com...
> On May 2, 11:11 am, arijitchatterjee...@.yahoo.co.in wrote:
>> Hi,
>> I have a silly doubt. Please tell me whether "Is Null" is a contraint
>> or not? If yes then why it does not show in sysconstraints view?
>> Regards
>> Arijit Chatterjee
> Sorry little modification instead of "Is Null" I want to say "Not Null"
>|||On May 2, 11:49 am, "Tibor Karaszi"
<tibor_please.no.email_kara...@.hotmail.nomail.com> wrote:
> It depends on who you ask. Technically, NOT NULL is not a constraint in SQL Server, if we by
> "constraint" mean what syntax we used for other constraints, like:
> ALTER TABLE ... ADD CONSTRAINT...
> So, in SQL Server, NOT NULL is more like a column attribute. Of course, NOT NULL does constraint
> what you are allowed to put in that column, so seen from that viewpoint, NOT NULL is a constraint.
> I believe that in ANSI SQL, NOT NULL is indeed a "constraint" similar to CHECK and FOREIGN KEY,
> possibly represented in the system catalog as such.
> --
> Tibor Karaszi, SQL Server MVPhttp://www.karaszi.com/sqlserver/default.asphttp://sqlblog.com/blogs/tibor_karaszi
> <arijitchatterjee...@.yahoo.co.in> wrote in message
> news:1178086362.445723.175660@.q75g2000hsh.googlegroups.com...
>
> > On May 2, 11:11 am, arijitchatterjee...@.yahoo.co.in wrote:
> >> Hi,
> >> I have a silly doubt. Please tell me whether "Is Null" is a contraint
> >> or not? If yes then why it does not show in sysconstraints view?
> >> Regards
> >> Arijit Chatterjee
> > Sorry little modification instead of "Is Null" I want to say "Not Null"- Hide quoted text -
> - Show quoted text -
Thanks a bunch...