Extracting N-ary Relationships Through Database Reverse Engineering

This paper presents an automatic process for reverse engineering the n-ary relationship tables from an operating relational database. This process performs the extraction of cardinality ratios by generating a set of SQL queries for each n-ary relationship table. We focus on realistic assumptions. We suppose that there are no constraints on the uniqueness of the key attribute names and the dependencies are not supposed to be known a priori. A PRO*C program has been implemented, it enables us to automatically build SQL queries via dynamic SQL. We also study the influence of the number of key attributes and the number of tuples upon the performance of our process.