Question

If I have a situation (which I do, but changing the situation is not an option) where I run a statement such as:

Update Table 1 Set Field 5 = 'Blah' Where Field5 IS NULL

And that statement runs at the exact same time multiple times, how can I avoid the same row being updated by multiple threads?

Answer 1

Maybe this is because of a “made up example” here, but that statement will already only run once for a given record.

Assume that Field5 is null:

Update Table 1 Set Field 5 = 'Blah' Where Field5 IS NULL

Now Field5 = ‘Blah’

Running this statement a second time…

Update Table 1 Set Field 5 = 'Blah' Where Field5 IS NULL

Will do nothing. The record will remain as it was from the first update as it is no longer included in the WHERE clause.