O'Reilly logo

UML and Data Modeling: A Reconciliation by David Hay

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

In the approach to entity/relationship modeling described in this book, there are three constraints on the treatment of super-/sub-types:

·         Completeness - Each instance of the super-type must be an instance of one of the sub-types. This is equivalent in UML to calling the super-type abstract. That is, in UML you can impose this constraint or not. In the version of entity/relationship modeling described here, the constraint always applies, but it can be finessed by adding a sub-type Other… (Other Organization, Other Geographic Area, etc.).

·         Exclusivity – No instance of the super-type may be an instance of more than one of the sub-types.

·         No multiple inheritanceEach sub-type may have only one super-type. ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required