7 November 2019
Database(18) -- E/R Model
by Jerry Zhang
Multiplicity of Binary E/R Relationships
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If each member of E can be connected by R to at most one member of F, then we say that R is many-one from E to F.
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If R is both many-one from E to F and many-one from F to E, then we say that R is one-one.
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If R is neither many-one from E to F or from F to E, then we say R is many-many.