Referential Integrity Revisited: An Object-Oriented Perspective
نویسنده
چکیده
Referential integrity underlies the relational representation of objeceoriented structures. The concept of referential integrity in relational databases is hindered by the confusion surrounding both the concept itself and its implementation by relational database management systems (RDBMS). Most of this confusion is caused by the diversity of relational representations for object-oriented structures. We examine the relationship between these representations and the structure of referential integrity constraints, and show that the controversial structures either do not occur or can be avoided in the relational representations of object-oriented structures. Referential integrity is not supported uniformly by RDBMS products. Thus, referential integrity constraints can be specified in some RDBMSs nonprocedurally (declaratively) , while in other RDBMSs they must be specified procedurally. Moreover, some RDBMSs do not allow the specification of certain referential integrity constraints. We discuss the referential integrity capabilities provided by three representative RDBMSs, DB2, SYBASE, and INGRES.
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