Extend MembershipUser or Profile to add FirstName property?

I currently store FirstName and LastName for users using the default SQL Server profile provider, and it is difficult to directly query these values in SQL since all the datapoints are stored in a single column. I want to make use of a database table that has FirstName and LastName columns to make it easier to query.

To do this, should I extend MembershipUser or the Profile? I'm wondering which method is more correct not which is easier to implement. Thank you.

 ASP.NET 2.0, SQL Server 2005.


 
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