Generating Narrations of Nested SQL Queries Using Context-free Grammars

In the software industry, Structured Query Language (SQL) remains a highly sought-after skill required by most employers. SQL is widely adopted as the preferred declarative language to manipulate data in relational databases. However, the process of comprehending written and new queries turns out to be difficult, especially for novices. To address this problem, a plethora of tools have been developed to assist a novice understand queries using different approaches via visualisation and narration. This paper describes a SQL Narrator designed using a Context-free Grammar that reads and generates narrations for queries using predefined templates. The SQL Narrator is able to narrate nested queries cascaded with balanced parentheses. The generated narrations can be used in assisting students to comprehend nested SQL queries in learning environments. A survey conducted on 161 participants showed that 98.1% agreed that they were able to understand nested queries using our SQL Narrator.