Quality Assessment for Embedded SQL

The access of information systems to underlying relational databases is commonly programmed using embedded SQL queries. Such embedded queries may take the form of string literals that are programmatically concatenated into queries to be submitted to the DBMS, or they may be written in a mixture of the syntax of SQL and a host programming language. The particular ways in which embedded queries are constructed and intertwined with the surrounding code can have significant impact on the understandability, testability, adaptability, and other quality aspects of the overall system. We present an approach to tool-based analysis of the quality of systems that employ embedded SQL queries. The basis of the approach is the identification and reconstruction of embedded queries. These queries are then submitted to a variety of analyses. For example, we chart the relationships of queries to the surrounding code and, via the control and data flow of that code, to each other. Also, we define a suite of metric extractors for embedded queries. Through a number of case studies, involving PL/SQL, Cobol, and Visual Basic, we show how the results of these analyses can be employed to make an assessment of various quality aspects related to the use of embedded queries.