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Cannot truncate table because it is being referenced by a FOREIGN KEY constraint

Posted on 2013-06-01
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Last Modified: 2013-06-08
Hello there,

How can I truncate a table which has foreign key constraints. I am in development and I need to truncate the tables.is there some easy way to this.

cheers
Zolf
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Question by:zolf
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7 Comments
 
LVL 22

Expert Comment

by:Kelvin Sparks
ID: 39213883
Use Delete FROM... instead. To use Truncate the FK has to be dropped. DELETE will allow a delete providing the records being deleted do not cause any RI issue.


Kelvin
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Author Comment

by:zolf
ID: 39213889
but the issue is that that delete will not start the pk from 1. I want the pk to be reset too which truncate does it for you. by the way what do you mean "the records being deleted do not cause any RI issue."
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LVL 22

Assisted Solution

by:Kelvin Sparks
Kelvin Sparks earned 250 total points
ID: 39213892
True,

But you could after the delete reset the identity seed.

DBCC CHECKIDENT (tablename, RESEED, 0)

would allow 1 to be the value of the identity seed for the next record in table 'tablename'

Kelvin
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LVL 22

Expert Comment

by:Kelvin Sparks
ID: 39213894
If you want to persist with truncate, then you have to drop each FK, perform the truncate, then recreate the FK


Kelvin
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LVL 23

Expert Comment

by:Racim BOUDJAKDJI
ID: 39214173
Note that the process to drop/recreate of constraint can entirely be scripted as well as the truncate itself.  You can generate entirely the drop/recreate of constraints.
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LVL 75

Accepted Solution

by:
Anthony Perkins earned 250 total points
ID: 39214544
DBCC CHECKIDENT (tablename, RESEED, 0)
Just be aware that in order to use this command you have to "be a member of the sysadmin fixed server role, the db_owner fixed database role, or the db_ddladmin fixed database role."
That is not always an option.
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Author Closing Comment

by:zolf
ID: 39232551
thanks
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