>so funtions that can be performed by relation algebra are a subset of the
>functions performed by a relational database?
>however isn't it required for a relational database to perform all the
>functions of relation algebra?
Saqib, there are multiple relational algebras. No db fully implements Codd's
specs. The degree to which a db like MySQL implement's Codd's rules and
algebra is just one arbitrary measure of 'relationality'. We have to decide
which features we want, and which we can do without.