Re: Entity modelling - newbie question.

Borris,

The classical treatment of Entity Relationship modeling does not include foreign keys at all.

Foreign keys are, in essence, one way to record relationship instances in a coherent way. Foreign keys form part of the relational model of data. The relational model and the entity-relationship model are distinct models of data, although they are closely related.

Some of the classical papers divide data models into three kinds: conceptual models, useful for recording the findings of data analysis;  logical models, useful for recording the aspects of data design visible to the accessors; and physical models, which include the design of all the features of the database, including those that are product specific, transparent to accessors, and/or driven by considerations of volume and load.

Some of these use the E-R model for conceptual modeling, the relational model for logical modeling, and a product specific extension of the relational model for physical modeling. Not everyone agrees with this outline, however.

Suit yourself. Received on Mon Jan 14 2002 - 10:46:37 CST