Techniques for automatically identifying undeclared composite key relationships in a database schema

Abstract

Techniques are described herein for automatically discovering undeclared PK-FK relationships between dimension tables and a fact table in situations where: the primary keys of the dimension tables (a) are not known, and (b) are composite keys, and the foreign keys of the fact table (a) are not known, and (b) are composite keys. The techniques involve removing from consideration all fact table columns that satisfy first removal criteria, and all dimension table columns that satisfy second removal criteria. Fingerprints are generated for the fact and dimension table columns that remain. Matched pairs (e.g. two fact table columns and two dimension table columns) are generated based on the columns that have not been filtered. The matched pairs are further filtered based on third removal criteria. The matched pairs that remain are then graded, and a PK-FK relationship is established based on the matched pair with the highest grade.