I occasionally run into issues where I would like to ensure that the values across two or three columns are not duplicated. At work we use Oracle, and I see that they add constraints when creating the columns. I am running mysql 5.0 and was hoping someone could give me the simple explanation of how to create constraints, and whether indexes' are needed for these or not.
I have tried reading the docs in this regard, but because I do not understand the concept I am having trouble translating to the actual creation of these. Thanks, Scott
