%0 Report %1 Wieringa1991 %A Wieringa, Roel %A de Jonge, Wiebren %D 1991 %K ORM database identifier roles %N IR-267 %R 10.1.1.16.3195 %T The identification of objects and roles - Object identifiers revisited %X In this paper we investigate several concepts that are known in database research for some time but which are still surrounded by some confusion. We start with the concepts of object identifier, surrogate and key and list the differences between these concepts, which in practice are often ignored. Sharpening these differences allows us to analyze the distinction between objects and roles that recently surfaced in the literature. Distinguishing objects from roles helps to avoid migration of objects between classes and thus the problems associated with it. We show that this distinction requires the use of role identifiers that, just as object identifiers, should be globally unique and unchangeable. We next show that using role identifiers requires a distinction between two essentially different kinds of inheritance relationships, is-a inheritance and played-by inheritance. These are often both treated as if they were one and the same kind of is-a relationship. The result of the discussio...

@techreport{Wieringa1991, abstract = {In this paper we investigate several concepts that are known in database research for some time but which are still surrounded by some confusion. We start with the concepts of object identifier, surrogate and key and list the differences between these concepts, which in practice are often ignored. Sharpening these differences allows us to analyze the distinction between objects and roles that recently surfaced in the literature. Distinguishing objects from roles helps to avoid migration of objects between classes and thus the problems associated with it. We show that this distinction requires the use of role identifiers that, just as object identifiers, should be globally unique and unchangeable. We next show that using role identifiers requires a distinction between two essentially different kinds of inheritance relationships, is-a inheritance and played-by inheritance. These are often both treated as if they were one and the same kind of is-a relationship. The result of the discussio...}, added-at = {2011-02-13T20:19:24.000+0100}, author = {Wieringa, Roel and de Jonge, Wiebren}, biburl = {https://www.bibsonomy.org/bibtex/2ce4355ea9a2e31bfbd812430a1da3249/voj}, doi = {10.1.1.16.3195}, institution = {Faculty of Mathematics and Computer Science, Vrije Universiteit}, interhash = {72ae9c563b6b5da81f0027456ac7aa5c}, intrahash = {ce4355ea9a2e31bfbd812430a1da3249}, keywords = {ORM database identifier roles}, number = {IR-267}, timestamp = {2011-02-13T20:19:24.000+0100}, title = {The identification of objects and roles - Object identifiers revisited}, year = 1991 }