What are Relational Database Management Systems? What is the need to test RDBMS?

Relational Database Management Systems cntains critical data which is updated by many applicatins and many end users. They provide important functionality as well. It is very important to test the functionality of relational database management systems. A regression suite should be made available and testing should be done on a regular basis.

The need to test a relational database management system is necessary because data is a very important asset and all the critical business related functionality is implemented in relational database management system. Generally, data professionals used to control changes and do formal testing but this approach did not proved to be efficient so because of the current approaches not being very efficient, there arises the need for relational database management system testing. Also, testing is a way to provide feedback that could be used to identify defects.

RDBMS testing should test the following :
- Black box testing at the interface which includes data values being persisted, data values being retrieved and stored functions and procedures.
- White box or clear box testing tests within the database. It includes scaffolding code which supports refactoring, unit tests, existence tests for database schema elements, view definitions, referential integrity rules, data invariants involving coloumns, data invariants for single column.

A test-first development(TFD) approach is used by agile software developers where a test is written before writing enough production code to fulfill that test.
- Add a test.
- Run the tests
- If it passes, again add a test otherwise make a little change and again run the tests.
- If it fails, again make a little change and run the tests.
- If it passes, the development stops.
- Once the test passes, again start over.

Test Driven Development(TDD) combines test first development and refactoring. When a new feature is implemented, the question whether this is the best design hwich enables the developer to add this feature is asked. If the answer is yes, then do the work and proceed. If the answer is no, design is refactored and then test first driven (TFD) is done.