nocheck when creating a constraint

i was looking at a database creation script and i have a bunch of
constraints being created with a nocheck on them. i think i know what
the nocheck does (don't check for data issues). i'm not sure why the
original coder would define them like this since there is no data to
begin with when the tables are built. am i missing something? does
this hurt the database table?
ALTER TABLE [dbo].[mytable] WITH NOCHECK ADD
CONSTRAINT [PK_mytable] PRIMARY KEY ([mytable_id]) ON [PRIMARY]That seems to be a stupid thing to do. You won't gain anything, and possibly just have a non-trusted
constraint which can lead to worse performance (non-trusted will limit some of the optimizations
that can be done).
--
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://sqlblog.com/blogs/tibor_karaszi
"Derek" <gepetto_2000@.yahoo.com> wrote in message
news:1178199834.825140.114810@.y5g2000hsa.googlegroups.com...
> i was looking at a database creation script and i have a bunch of
> constraints being created with a nocheck on them. i think i know what
> the nocheck does (don't check for data issues). i'm not sure why the
> original coder would define them like this since there is no data to
> begin with when the tables are built. am i missing something? does
> this hurt the database table?
>
> ALTER TABLE [dbo].[mytable] WITH NOCHECK ADD
> CONSTRAINT [PK_mytable] PRIMARY KEY ([mytable_id]) ON [PRIMARY]
>|||Derek,
See this blog from SQL Server MVP Hugo Kornelis.
Can you trust your constraints?
http://sqlblog.com/blogs/hugo_kornelis/archive/2007/03/29/can-you-trust-your-constraints.aspx
AMB
"Derek" wrote:
> i was looking at a database creation script and i have a bunch of
> constraints being created with a nocheck on them. i think i know what
> the nocheck does (don't check for data issues). i'm not sure why the
> original coder would define them like this since there is no data to
> begin with when the tables are built. am i missing something? does
> this hurt the database table?
>
> ALTER TABLE [dbo].[mytable] WITH NOCHECK ADD
> CONSTRAINT [PK_mytable] PRIMARY KEY ([mytable_id]) ON [PRIMARY]
>