Extending Databases to Support Data Manipulation with Functional Dependencies: a Vision Paper

Abstract: In the current paper, we propose to fuse together stored data (tables) and their functional dependencies (FDs) inside a DBMS. We aim to make FDs first-class citizens: objects which can be queried and used to query data. Our idea is to allow analysts to explore both data and functional dependencies using the database interface. For example, an analyst may be interested in such tasks as: "find all rows which prevent a given functional dependency from holding", "for a given table, find all functional dependencies that involve a given attribute", "project all attributes that functionally determine a specified attribute". For this purpose, we propose: (1) an SQL-based query language for querying a collection of functional dependencies (2) an extension of the SQL SELECT clause for supporting FD-based predicates, including approximate ones (3) a special data structure intended for containing mined FDs and acting as a mediator between user queries and underlying data. We describe the proposed extensions, demonstrate their use-cases, and finally, discuss implementation details and their impact on query processing.