Amplify 发表于 2025-4-1 03:15:43

Local referential integrity,te object. For example, in production planning an employee of some department may only be scheduled to work on machines belonging to the same department. Usually, such a constraint must be stated explicitly by a predicate as “add on” to a database schema. Object-oriented data models have become popu
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查看完整版本: Titlebook: Entity-Relationship Approach - ER ‘92; 11th International C G. Pernul,AM. Tjoa Conference proceedings 1992 Springer-Verlag Berlin Heidelber