Study on the static analysis and the similarity comparing of SQL code

To address the problem of assessing the SQL code automatically in an E-learning system, this paper offers a way to calculate the similarity between SQL codes using the static analysis technology. We use the regular expressions, NFA and DFA technology to analyze the code and then generate the AST of the source code and target code. Based on the ASTs created before, the method proceeds the measuring by calculating the similarity between ASTs using tree edit distance and taking this as the similarity between SQL codes.