|Title||:||XData: Testing and Grading SQL Queries|
|Speaker||:||S Sudarshan (IIT Bombay)|
|Details||:||Tue, 18 Apr, 2017 11:00 AM @ BSB 361|
|Abstract:||:||Grading of student SQL queries is usually done by executing the queries on sample datasets, which may be unable to catch many errors, and/or manually checking the queries, which can be tedious and error prone. The XData system developed at IIT Bombay helps detect errors in SQL queries by generating multiple datasets tailored to show the difference between a correct query and an erroneous query that is a mutation of a correct query. Datasets generated by the system can be used to test correctness of SQL queries written by programmers, as well as to detect errors in student SQL queries by comparing the results with that of a correct query. The job of data generation is achieved by creating appropriately defined constraints, and feeding them to an SMT solver to get the required datasets.
For grading SQL queries however, just finding errors is not sufficient, since students need to be given partial marks based on how close to correct their query is. We have therefore recently extended the XData system to also perform partial marking, using a series of canonicalization steps to remove irrelevant syntactic differences between queries, before comparing them.
We have now released the XData system, with comprehensive Web based interfaces for students and instructors, and integration with LMSs such as Moodle.
About the speaker: S. Sudarshan is the Subrao M. Nilekani Chair professor in the Dept. of Computer Science and Engg. at IIT Bombay. His research interests are broadly in the area of database systems, with a focus on query processing and query optimization. He is co-author, with Silberschatz and Korth, of a widely used textbook, Database System Concepts, now in its 6th edition. He is thrilled and deeply honoured to have been awarded the DAA award by IIT Madras.