Data corruption during testing

Data corruption during testing

How often do find corrupt data in testing databases. Sometimes corrupt data results in various system failures that were not really the code errors or bugs. This is a challenge that testers may face while testing an application that has data dependency.

Generally more than one tester works on these applications simultaneously and as we all know testers are good at modifying data as per our needs. In the process we modify data, perform our testing and then forget about the data that we modified it sounds so easy going and cute, correct? But if someone else picks up that modified data and performs another operation, there is a possibility that the testing may fail. Then we are happy that we found a bug, we log a bug, and approach a developer like a master telling him that there is a major bug in the system. The developer will then debug the code for the bug and find that there is nothing wrong with the code, he again approach you and say that the code is just fine. Then how did the bug arise?

The answer here is that the bugs have been encountered due to data discrepancy in the database. The code would just run fine on the correct data but as the data is incorrect, the code is unable to determine the correct behaviour that should be performed for such "discrepant" data

Data discrepancy is as serious issue as a major code error. Just imagine a newspaper saying "9000 people killed in bus accident" while it should say "9 people killed in a bus accident". The impact is huge. It’s just like presenting an incorrect application to the client. It may even result in a very angry client or a client laughing like it is taunting you. The end result is EMBARRASSMENT!!!

There are solutions to prevent data discrepancy in a database.

1. Take a backup: Before modifying any data in the database take a backup of the database to ensure that if any woolly mammoth is encountered we can make it disappear by a database restore.

2. Revert back data manually: If you think database backup and restore are too lengthy process and there is not enough time for such activity, just revert back the data that you modified to its original state. This can be done using an UPDATE SQL query.

3. Division of data: Data can be divided among the number of testers working on the application. This helps as each member performs functionality on the data provided to them and hence keeps the data very much clean.

4. Minimal Use of Update and Insert: While using SQL, the use of update and insert should be minimal and should be used only if required. Don't just use update and insert just for fun in the testing database.

5. Ask before you do: One should always ask a DBA or the senior database analyser for any changes being made to the testing database. This will ensure that the DBA is aware of the changes and can handle any data related discrepancy in the database.

Thanks,

Mohit Bhatia