Current RDBMS technology provides little support for building temporal databases. The paper describes a methodology and a CASE tool that is to help practitioners develop correct and efficient relational data structures. The designer builds a temporal ERA schema that is validated by the tool, then converted into a temporal relational schema. This schema can be transformed into a pure relational schema according to various optimization strategies. Finally, the tool generates an active SQL-92 database that automatically maintain entity and relationship states. In addition, it generates a temporal ODBC driver that encapsulates complex temporal operators such as projection, join and aggregation through a small subset of TSQL2. This API allows programmers to develop complex temporal applications as easily as non temporal ones.