Architecture and Data Blog

Thoughts about intersection of data, devops, design and software architecture

8 Techniques for testing migration of data from legacy systems

Many of the projects we end up working on are replacing existing systems with existing data either wholly or in part. In all of the above projects we end up writing data migration or data conversion code to move the data from legacy systems to the new systems. Many stake holders of the project such as business users, project managers, business analysts really care about the data conversion scripts and the quality of the conversion.

Testing in data conversion projects

When working on projects involving Conversion of data or Migration/Moving of data from a legacy database. The testing effort is enormous and testing takes a lot of time, some test automation can help this effort. Since data is moved/changed from a source database to destination database, we can write sql which should provide results for the types of tests you want to perform, for example: write a sql to give us number of customers, write a sql to give us account balance for a specific account.

Database Testing revisited

Some time ago I wrote about what it means to do database testing.. more I think about this and having had some strange situations recently I want to add more to the list of things we should be testing. Persistence Layer. We should persist the objects to the database using the applications persistence layer and retrieve the objects using the same mechanism and test that we get the same object back.

Database Testing

What does it mean to test your Database? usually when someone mentions database testing, what is that they want to test. The application code that interacts with the database, or the sql code the resides in the database like stored procedures and triggers etc. I see all these aspects to database testing as important. Testing the applications persistence mechanism We should test that the application persists what its supposed to save and retirive the data using SQL and see if the database contains the same information that is being saved, this kind of testing makes sense when the application has complex persistence layer.