In the summary of this part I'd want to recommend following:
Try to find a query which causes inconsistent behavior
Use log files:
Analyze what is wrong, then solve the problem using your findings
Below I place a list of methods which we studied in the first part.
Method #1: use output operator to output query in exactly same way in which RDBMS gets it.
Method #2: use general query log if you need to find which exact query causes wrong behavior of your application.
Method #3: after you found a query which causes the problem run it using command line client and analyze result.
Method #4: try to modify SQL in such a way what you get correct result. Use search engines to find a workaround.
Method #5: use EXPLAIN EXTENDED for finding how optimized (and executing) SQL query.
Method #6: convert DML queries to corresponding SELECT to examine which rows will be modified.
Method #7: repeat your scenario backward step-by-step until you found the problem query.
Method #8: always check result of the query! Use means of your connector or interface of interactive client.
Method #9: tune your application in such a way so it will write queries to log files itself.
Method #10: use MySQL Proxy or any other proxy.
Author 2010 Sveta Smirnova
COPYRIGHT © 2010 S.Smirnova and S. Lasunov