June 2010
Intermediate to advanced
266 pages
5h 55m
English
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Chapter 8
Universal Antipatterns
An antipattern is a characterization of a common software flaw. When you find an antipattern, substitute the correction. Universal antipatterns are antipatterns that you should avoid for all applications.
8.1 Symmetric Relationship Antipattern
8.1.1 Observation
An entity type has a self relationship with the same multiplicity and role names on each end. Typically this is a many-to-many self relationship. Symmetric relationships can be troublesome for programming and are always troublesome for relational databases.
8.1.2 Exceptions
There are no exceptions for relational database designs. Avoid symmetric relationships.
8.1.3 Resolution
Promote the relationship to an entity type in its own right. The improved model ...
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