On 4 April 2011 15:55, Keean Schupke <ke...@fry-it.com> wrote: > Yes, it already has well defined set operations. Solid is a matter of > testing by enough people (and if you wanted to try it and feed back that > would be a start). Fast should not be a problem, as the SQL database does > all the heavy lifting. > > In more detail, Codd's six primitive operators are project, restrict, > cross-product, union and difference. Relations are an extension of Sets, so > intersection and difference on compatible relations behave like they would > on sets. >
I missed 'rename' from my list of Codd's operators. Our 'project' function provides both project & rename, so I overlooked it. > ... > Cheers, Keean.