The Chen notation
The Chen notation in Figure A.3 was the original entity–relationship modelling notation proposed by Peter Chen in his paper The Entity-Relationship Model – Toward a Unified View of Data (Chen, 1976) and the notation, with some refinements, is still in use today in a number of environments.
FIGURE A.3 A data model in Chen notation
Entities are represented by boxes, relationships by diamonds and attributes by ellipses attached to the entity boxes. Relationships can be ‘n-ary’, in that more than two entities may be related by a single relationship. Hence the PARTY ROLE TYPE entity of Figure A.1 is represented by the ‘has role ...
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