Martin Gogolla | Akateeminen Kirjakauppa

This text presents a comprehensive introduction to an
extended Entity-Relationship model both on a conceptual and
on a formal, mathematicallevel. In addition to the
primitives given by the data model the text introduces a
language for the formulation of constraints in order to
restrict database states to consistent ones. The text
explains an implementation of the approach chosen in the
logic programing language PROLOG and discusses in this
context the computational power of the proposedcalculus.
The extended Entity-Relationship calculus is used to define
the meaning of the relational query language SQL. A nice
feature of the approach is that it becomes possible to prove
language properties on a sound mathematical basis.