In large integration projects one is often confronted with poorly documented databases. One possibility to gather information on database schemas is to search for INclusion Dependencies (IND). These provide a solid basis for deducing foreign key constraints - as they are pre-condition for potential (semantically valid but missing) foreign key constraints. In this paper, the authors present and compare several algorithms to identify unary INDs. The obvious way is to utilize an appropriate SQL statement on each potential IND to test its satisfiedness.