Computer Assisted Assessment of SQL Query Skills

Structured Query Language (SQL) is the dominant language for querying relational databases today, and is an essential topic in introductory database courses in higher education. Even though the language is syntactically simple, relatively concise, and highly structured, students experience many difficulties while learning to express queries in SQL. In recent years a small number of software tools have been proposed to help students learn to write query statements and to assess their querying skills. In this paper we compare and evaluate existing tools mainly from the perspective of database theory and practice, but also from a pedagogical perspective. Addressing the deficiencies and opportunities uncovered by the evaluation, we then introduce SQLify, a new tool that extends the current state of the art by incorporating semantic feedback, enhanced automatic assessment based on database theory, and peer review to arrive at a richer learning experience for students, as well as consistent assessment results and reduced marking for instructors.