Retro-Erdds: Reverse Translator of E-Rdesigned Relational Schemas

郭振源(Yuan-Chen Kou) ； Frederick Springsteel

《資訊縮影管理》 16期 (1990/03) Pp. 50-51

並列摘要

A new solution is presented for the data engineer's inverse mapping problem: from a relational database schema (Robs) to construct a corresponding entity relationship diagram (ERD). In the forward direction from extended ERDs to relational DB schemata, there is a well known, much studied ERD conversion algorithm (ENSS; MMR8R 5C881. The inverse mapping problem is difficult because to one ROBS there may correspond many ERDs, or none if the schema is not well formed, so it not clear bow to define a mapping in Ibis direction. [Cf. Fig. I.) [SK90) Nonetheless, it would be desirable to have some criteria that help choose a moot representative ERD whenever possible, so that the benefits of E-R visualization and analysis [SC89] can be applied to: RDBSs, even after their relation schemes have had changes made to them.