How to deal with concurrent updates in databases?

Question

What\'s the common way to deal with concurrent updates in an SQL database ?

Consider a simple SQL schema(constraints and defaults not shown..) like

c         


        

Answer 1

If you store a last update timestamp with the record, when you read the value, read the timestamp as well. When you go to update the record, check to make sure the timestamp matches. If someone came in behind you and updated before you, the timestamps would not match.