Re: Is a function a relation?
Date: Mon, 29 Jun 2009 08:01:06 -0700 (PDT)
Given a relation type (i.e. schema), there are a number (possibly infinite) of relation values that conform to that type. The type and the values of that type are all abstract and carry almost no information. >>
The cardinality of un-ary relation subtype can *not* exceed the cardinality of the relation supertype. That is a constraint imposed by how a relation is defined. Received on Mon Jun 29 2009 - 17:01:06 CEST