Data Quality and Code Quality

Posted by Pramod Sadalage on Thursday, February 15, 2007

Recently we had peculiar problem. Some of the data in the database was not being created in a proper fashion. Once we found that out we fixed the problem in the application. The customer still had the perception that the code is still broken, because the fixed code was now interacting with the data that was broken (since it was created much earlier by code that was broken). Data has a life of its own (more on this later)

So I started thinking (this happens very rarely) about data quality. Does improved data quality give a perception of improved code quality? Does poor data quality drag down the perception of code quality? Anyway the effort invested in code quality can be negated if Data Quality is not thought about!.

When unit tests could be written to flush out design/code quality problems in the application. what could be done to improve data quality, what kind of tests could be written? Would these tests apply to the design of the database or to the quality of the data.