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Data Modeling Made Simple with ER/Studio Data Architect by Steve Hoberman

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APPENDIX C

Glossary

abstraction

Abstraction is the removal of details in such a way as to broaden applicability to a wider class of situations, while preserving the important properties and essential nature of concepts or subjects. By removing these details, we remove differences and, therefore, change the way we view these concepts or subjects, including seeing similarities that were not apparent or even existent before. For example, we may abstract Employee and Consumer into the more generic concept of Person. A Person can play many Roles, two of which are Employee and Consumer.

alternate key

An alternate key is a candidate key that although unique, was not chosen as the primary key, but still can be used to find specific entity instances. ...

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