some high-level language constructs for data of type relation
For the extension of high-level languages by data types of mode relation, three language constructs are proposed and discussed:- a repetition statement controlled by relations- predicates as a generalisation of boolean expressions- a constructor for relations using predicates.The language constructs are developed step by step starting with a set of elementary operations on relations. They are designed to fit into PASCAL without introducing too many additional concepts.
high-level language data type language extension relational model data base non-procedural language relational calculus