SQL Server - Auto-incrementation that allows UPDATE statements

Question

When adding an item in my database, I need it to auto-determine the value for the field DisplayOrder. Identity (auto-increment) would be an ideal solution, but I need to be

Answer 1

One thing you should do is to add commands so that your procedure's run as a transaction, otherwise two inserts running at the same time could produce two rows with the same value in DisplayOrder.

This is easy enough to achieve: add

begin transaction

at the start of your procedure, and

commit transaction

at the end.