only do update if there is not a unique key constr

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only do update if there is not a unique key constr

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Topic

MyronCope
Starting Member

46 Posts

Posted - 2008-01-15 : 12:59:59

Question: i have to do an update on a table that has a nested index of three fields. however i'm only getting one field as a parameter to work with and i am getting a constraint because there cannot be duplicate records.

Is there a way to only do the update code if the unique key constraint is not thrown? i was thinking about doing this in an if statement but the problem is i do not have all three keys that i can use to do the right query. thanks

dataguru1971
Master Smack Fu Yak Hacker

1464 Posts

Posted - 2008-01-15 : 18:40:03

I am assuming you mean primary key instead of index?

You would update something like this I am guessing..

Update [Table]
Set [Column] = @Parameter
Where @parameter not in (Select [Column] FROM [Table])

Poor planning on your part does not constitute an emergency on my part.

visakh16
Very Important crosS Applying yaK Herder

52326 Posts

Posted - 2008-01-15 : 22:51:23

or:-

Update 
Set [Column] = @Parameter
FROM [Table] t1
LEFT OUTER JOIN
(Select distinct [Column] FROM [Table] WHERE [Column]=@Parameter)t2
ON t2.[Column]=t1.[Column]
WHERE t2.[Column] IS NULL

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