Secret Orange Web Log

Ok, just a quick one...this had me stumped for over an hour!

I wanted to simply update one column on a "user" object in the database. So, I retrieved the object from the DB, set the new value and called SubmitChanges. I then get hit with a ChangeConflictException.

It was a fresh DataContext and the property in the DBML file looked OK. I then checked the output of the SQL and it looked something like:

UPDATE User
SET CalendarID = @p0
WHERE 0 = 1

What was the 0 = 1 where clause all about? As it turns out I think its meant to be some kind of LINQ to SQL optimisation gone wrong...anway this started to lead me down the right path and I ended finding out that it was another "user" property in the DBML file that was causing the problem. I had a column name "DisplayName" which was set as NULL in the DB but not nullable in the DBML file. Fixing this seems to have solved the problem...even though the DisplayName property had nothing to do with the UPDATE.