Is DEFAULT a constraint?

[Eric Bragas]

Hi,

I see the following in Books Online: CONSTRAINT--Is an optional keyword
indicating the beginning of a PRIMARY KEY, NOT NULL, UNIQUE, FOREIGN
KEY, or CHECK constraint definition...

But I have a table column defined as follows:

[MONTH] [decimal] (2, 0) NOT NULL CONSTRAINT
[DF__TBLNAME__MO NTH__216361A7] DEFAULT (0)

My question: Is "DEFAULT" a constraint, or is it called something else?

Thanks,
Eric

[Erland Sommarskog]

Re: Is DEFAULT a constraint?

Eric Bragas (ericbragas@yah oo.com) writes:

I see the following in Books Online: CONSTRAINT--Is an optional keyword
indicating the beginning of a PRIMARY KEY, NOT NULL, UNIQUE, FOREIGN
KEY, or CHECK constraint definition...
>
But I have a table column defined as follows:
>
[MONTH] [decimal] (2, 0) NOT NULL CONSTRAINT
[DF__TBLNAME__MO NTH__216361A7] DEFAULT (0)
>
My question: Is "DEFAULT" a constraint, or is it called something else?

There are actually two sorts of defaults: bound defaults and default
constraints. Bound defaults are deprecated, but are useful when you
bind them to types.

What you have above, is indeed a default constraints.


--
Erland Sommarskog, SQL Server MVP, esquel@sommarsk og.se

Books Online for SQL Server 2005 at

http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/books.mspx

Books Online for SQL Server 2000 at

http://www.microsoft.com/sql/prodinfo/previousversions/books.mspx

[Eric Bragas]

Re: Is DEFAULT a constraint?

Thank you for the clarification.