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Return to Projeto e Otimização/Database Design and Optimization This paper proposes the Temporal Versioned Constraint Language (TVCL), which provides a declarative and non ambiguous way to user specification of constraints for temporal databases with versions support, based on the Temporal Versions Model (TVM). This language gives support to time and versions characteristics of data and of the constraints themselves, allowing the definition of constraints validity intervals, the storage of their update histories and distinct constraint versions at the same time, considering current or historical data of datasets versions. In order to specify constraints, the TVM query language and a data modification language are used. Also, the TVCL expressive power is analyzed based on a constraints classification. ![]() ©2006 Association for Computing Machinery |