Question

I’m trying to remove the need to explicitly lock a table with the following code but from reports I’ve been getting it may be possible that the parameter and value in the row are suffering from a race condition.

    Declare @NextNumber Int;

Update
    MyParameterTable
Set
    NextNumber = NextNumber + 1,
    @NextNumber = NextNumber + 1

Select @NextNumber As NextNumber;

Hopefully you can see it is just incrementing an integer and returning the result. I was under the impression that an update statement formatted in this manner would handle the necessary locks but as I say, it might be the case that the parameter is beign assigned outside of the update lock.

Can anyone throw some light on this and suggest an alternative?

Regards

Ryan

Answer 1

That will lock fine, but you can do it in a three-part equality statement:

Declare @NextNumber Int;

Update
    MyParameterTable
Set
    @NextNumber = NextNumber = NextNumber + 1

Select @NextNumber As NextNumber;