I presented a talk called "Enterprise Data Validation" at the Hampton Road .NET User Group this evening. The premise was simple. Data validation needs to happen in all the tiers of a modern application but the validation rules should be defined only once to avoid synchronization errors. In this talk, I showed how to extend SQL Server using extended properties to store regular expressions for data validation as column metadata. I also showed how to add a regular expression matcher to SQL Server using the SQL CLR and how to add check constraints to invoke the regular expression parser. Then I built a WCF service to query the validation metadata to make it available in other application tiers. I quickly assembled WCF service host and client showed how you could bring all of the elements together to create a working Enterprise Validation solution.

Download the SQL Scripts (20.06 kb)

I spoke at the Charlottesville .NET User Group this week and at the Raleigh Code Camp. I cheated and did the same presentation to both groups. Call me lazy but, in the middle of planning our own Code Camp in Richmond, I really didn't want to prepare two separate talks. I did a talk back at CodeStock 2009 on a similar topic back in June 2009 but it's evolved a lot since then based on my own growth and understanding. You can find the code and slides below.