Comments on: SQL SERVER – Disable CHECK Constraint – Enable CHECK Constraint

By: dhanalakshmi

dhanalakshmi — Tue, 14 May 2013 07:47:54 +0000

use swathy2
create table paydept( emp_id int check(emp_id>0),firstnam varchar(50),lastnam varchar(50))
insert into paydept values(’1′, ‘jam’,'varatha’)
select * from paydept
insert into paydept values(’2′, ‘dhana’, ‘lakshmi’)
Alter table paydept
drop check emp_id

in this table for dropping the table error is coming

like Incorrect syntax near the keyword ‘check’.

please give me the reply how do i drop the check in this table

By: Manqoba

Manqoba — Mon, 08 Apr 2013 16:16:57 +0000

Hi,
I am currently a student at a University of Technology. I would like to know if I don’t want to delete, is it possible to “freeze/disable” a record in sql server 2008 R2?

By: Sinisa

Sinisa — Fri, 30 Nov 2012 09:06:27 +0000

I did it when I had to import several related tables and didn’t want to bother with order of the importing. It was from one server, file transfer, flat file import…and since the files were different sizes, they arrived in different order so I disabled every check and simply imported the files as they arrived.

@iDesi, it’s not typo, it works exactly as written

By: iDesi

iDesi — Tue, 20 Nov 2012 14:40:03 +0000

There’s a typo in your blog entry. “World CHECK is used twice” should be “word”. A very helpful blog though. :)

By: iDesi

iDesi — Tue, 20 Nov 2012 14:39:11 +0000

There’s a typo in your blog post. “World CHECK is used twice” should be “word”. Very helpful blog though :)

By: SQL SERVER – Weekly Series – Memory Lane – #003 « SQL Server Journey with SQL Authority

Sat, 17 Nov 2012 01:31:36 +0000

[...] Enable or Disable Constraint This is very simple script but I personally keep on forgetting it so I had blogged it. Till today, I keep on referencing this again and again as sometime a very little thing is hard to remember. [...]

By: babuni

babuni — Fri, 21 Sep 2012 06:55:16 +0000

hi pinal
i was using this query to disable my check constraint and it is done successfully but while i wanted to enable this one it is showing an error saying that
The ALTER TABLE statement conflicted with the CHECK constraint “ck_address_emp”. The conflict occurred in database
please solve it…

By: D-wanna

D-wanna — Tue, 18 Sep 2012 15:13:00 +0000

When re-enabling the constraints, it’s imperative that you tell SQL Server to check the existing population:
ALTER TABLE HumanResources.Employee WITH CHECK CHECK CONSTRAINT ALL;
(Note that the double CHECK is *not* a typo!)

Failing to do so, as in your code, makes the constraints non-trusted. The optimizer will now no longer use these constraints to optimize execution plans.

More info at http://sqlblog.com/blogs/hugo_kornelis/archive/2007/03/29/can-you-trust-your-constraints.aspx

By: hao

hao — Fri, 07 Sep 2012 05:55:56 +0000

correct!

By: sudhakar

sudhakar — Mon, 30 Jul 2012 12:10:04 +0000

Hi,

I need to alter a column datatype. so i have disabled all the constraints which are depending on the column. But still i could not run the alter statement. It gives
Msg 5074, Level 16, State 1, Line 1
The object ‘FK_something’ is dependent on column ‘ALIAS’.

But if i run this script

SELECT name, tbl = object_name(parent_obj)
FROM sysobjects
WHERE objectproperty(id, ‘CnstIsDisabled’) = 1

it shows all the constrains which i was disabled.

any one help me!

By: Nikhildas

Nikhildas — Thu, 03 May 2012 05:08:21 +0000

Thanks pinal sir..

Its very helpful…

By: Sanju

Sanju — Fri, 16 Mar 2012 05:17:41 +0000

There is no mistake in your ‘check’ but if you check your text, there is some mistake.

Let us have a look…
“…. the world CHECK is used twice – WITH CHECK CHECK CONSTRAINT”

Just go before the first check, world… it should be word but not world… ;)

I know, its not a technical discussion but still a suggestion to correct it.. :)

By: SQL SERVER – Various Ways to Create Constraints – Quiz – Puzzle – 17 of 31 « SQL Server Journey with SQL Authority

Wed, 18 Jan 2012 01:31:48 +0000

[...] Creating Table Creating Primary Key, Foreign Key and Default Constraint How to ALTER CONSTRAINT Disable CHECK Constraint – Enable CHECK Constraint Query to Display Foreign Key Relationships and Name of the Constraint for Each Table in Database [...]

By: Golden

Golden — Sun, 08 Jan 2012 13:21:22 +0000

I am updating the tables in 13 databases on my one application. Many of them reffering to each other. I have disabled the constraints, updated tables and enabled.

Just I want to know if any impact on database health by doing this changes in constraints.

Response required.

Thanks
AKHILESH

By: Senthil Kumar K.S

Senthil Kumar K.S — Thu, 15 Dec 2011 11:24:32 +0000

How to check status of column constraint ( enabled or disabled)

By: Senthil Kumar K.S

Senthil Kumar K.S — Thu, 15 Dec 2011 11:02:04 +0000

How to check status of column constraints.(Enable or disabled).

By: Jayaram

Jayaram — Fri, 02 Sep 2011 05:30:01 +0000

How to maintain check constraint with two databases say db1 and db2?

By: KumarHarsh

KumarHarsh — Thu, 07 Oct 2010 11:07:50 +0000

Hi,
Suppose,I disable the index.
Perform some task
Again I enable it.
when I enable the index again whether the data will be reindexed or it will remain same.
If it gets reindexed how long will it take to reindex for 13 crore / 130 million record.

Thanks.

By: Niraj Singh Pawar

Niraj Singh Pawar — Tue, 20 Jul 2010 11:08:32 +0000

how to use Check constraint in If conditions

By: Ryan Anthony

Ryan Anthony — Thu, 12 Nov 2009 21:15:29 +0000

You don’t need to use With Check when re-enabling a check constraint, it accomplishes something entirely different than re-enabling the check constraint. By default for Alter Table, With Nocheck is used for re-enabling check constraints. Specifying With Check looks at all existing data to make sure it satisfies the check constraint. If you can safely assume that it already does, then you don’t need to specify that.

I disable check constraints to get replicating dbs that have gotten out of sync back in sync.

By: Brian Tkatch

Brian Tkatch — Thu, 12 Nov 2009 14:19:29 +0000

@Dave so you disabled the NOT NULL CONSTRAINT?

@Imran So you disable the FK.

I think FK is the most likely CONSTRAINT to be disabled, and NOT NULL being a close second. A CHECK CONSTRAINT (not the one for NOT NULL which although is a CHECK CONSTRAINT, is specified differently) is not really disabled too often.

It would be interesting to see what types a CHECK CONSTRAINT are actually used, and which types are disabled.

By: Imran Mohammed

Imran Mohammed — Thu, 12 Nov 2009 04:20:07 +0000

I remember, We had a huge database that collects statistics around 45 GB and we had very less space on server, it created many problems.

Finally one fine day, they asked me if I could help, they said, they want to clean historical data. Vendor suggested them to use front End to Purge (Delete) data. It was like tons of records… and would take for ever more than a day, to purge data, because you could purge very few records at one time.

I studied their database and came to conclusion that there are only 3 tables that had huge amount of data… and other tables were referring to them.

I gave them a solution to Truncate those 3 tables. For that I had to drop foreign key constraint. I dropped Forign Key Constraint, Truncated tables and built Foreign Key constraint again.

Boom… 3 seconds… Database size came to less than 0.5 GB.

Result: I was awarded DBA of the week :)

Note: I did enough research on the database, and I ensured that truncating data from 3 tables wont effect application.

~ IM.

By: Dave

Dave — Thu, 12 Nov 2009 02:23:13 +0000

I have disabled FKs in the past for purposes of data loading, where data coming into constrained column was going to have nulls.

After loading and cleaning the constraints were re-enabled.