I was wondering what the general recommendation is for Entity Framework in terms of data validation. I am relatively new to EF, but it appears there are two main approaches to data validation. The first is to create a partial class for the model, and then perform data validations and update a rule violation collection of some sort. This is outlined at http://msdn.microsoft.com/en-us/library/cc716747.aspx The other is to use data annotations and then have the annotations perform data validation. Scott Guthrie explains this on his blog at http://weblogs.asp.net/scottgu/archive/2010/01/15/asp-net-mvc-2-model-validation.aspx. I was wondering what the benefits are of one over the other. It seems the data annotations would be the preferred mechanism, especially as you move to RIA Services, but I want to ensure I am not missing something. Of course, nothing precludes using both of them together. Thanks John