What is QRW?

QRW is a SQL query rewriter written in Java. Given definitions of database schemas, and views, QRW can rewrite a SQL query referring to database relations to a SQL query that only refers to predefined views. QRW has following features:

• Always try to produce equivalent rewriting;
• Produce CE rewritings or maximally contained rewriting;
• Provide 3 algorithms, TCM-MiniCon, E-MiniCon and MiniCon, for user to choose
• Handle basic conjunctive queries with comparison predicates. Do not support query with aggregation or sub-queries.

How to use QRW?

QRW consists of two parts:

• A class library providing rewriting interfaces. See QRW API documentation for details.
• A query rewriting application using the library above. This application provides both command line and GUI interfaces. The instruction of this application can be found here.