butes on your class properties of data object classes (see the ADO.NET Code Generator link below for a sample) to flag whether the database will accept null values for that particular property.  This will enable the class to optionally self validate itself (see ADO.NET Code Generator CustomAttributes.cs class for a code sample) versus having to write test code or business layer validation code for each and every class.  This can be a huge time saver. f. I use custom attributes to dynamically populate class pro - jcran