How to Obtain Query from PreparedStatement for Debugging

In Java, java.sql.PreparedStatement enables efficient execution of parameterized queries by allowing dynamic binding of parameter values. Occasionally, during debugging, it becomes necessary to review the complete query before its execution. This article explores how to retrieve and print this query.

Examining PreparedStatement#toString()

As per the JDBC API, there is no explicit method for obtaining the final query string. However, with some luck, the specific JDBC driver in use may offer this functionality through PreparedStatement#toString(). For instance, PostgreSQL 8.x and MySQL 5.x drivers have been known to return the complete SQL when toString() is invoked:

System.out.println(preparedStatement);

Alternative: Statement Wrapper

If the employed JDBC driver lacks this feature, a statement wrapper that logs all calls to setXxx() methods can be utilized. When toString() is invoked, the wrapper generates and provides the SQL string based on the recorded information. A notable library that performs this task is P6Spy.

Additional Considerations

Developers are advised to submit enhancement requests to their respective JDBC driver development teams to encourage the implementation of a comprehensive toString() method for debugging purposes.