Using LINQ transformation patterns to evaluate SQL queries

The SQL Lightweight Tutoring Module (SQL-LTM) is a software tool designed to evaluate the correctness of SQL queries in order to provide useful feedback to the students and guidance in their effort to learn SQL. The XML representations of the queries are processed and analyzed in several steps in order to achieve this. One important step in this process is to transform the query into a logically equivalent one, having a different structure, which is easier to further analyze. This paper focuses on the query transformation patterns and their key role in the semantic evaluation of SQL queries of an arbitrary complexity.