I just came across an interview with Senior Product Manager for SQL Data Services (SDS), Niraj Nagrani at http://visualstudiomagazine.com/blogs/weblog.aspx?blog=3577. The interviewer asked a question that I think could be misconstrued:
- Are you basically not going to be offering SDS with the EAV tables any more?
I think I know what the interviewer was trying to say but after reading that question one may deduce that:
- The current (but soon to be axed) version of SDS is an Entity-Attribute-Value (EAV) model
- It will not be possible to host EAV models the future version of SDS
Neither of those is the case. Firstly, whilst the current incarnation of SDS is (underneath the ACE model abstraction) built upon an EAV model (which I think is what the interviewer was alluding to) I don’t believe its true to say that the ACE model with which a user interacts is an EAV model in itself.
Secondly, it is absolutely not the case that it won’t be possible to host EAV models on the future incarnation of SDS. That version of SDS will be built upon SQL Server 2008 which contains the new sparse column feature – a perfect storage mechanism for EAV models. Moreover, its more than possible to build EAV models on a traditional relational database (I’ve done it myself) and if you want to know how to do it then go and read Arnie Rowland’s excellent treatise on the subject at Through the Looking Glass: Elegant -or Not?.
Strangely the interviewee seemed to misconstrue the question in a different way again because in his answer he started banging on about ADO.Net Data Services which has got nothing to do with EAV models.
-Jamie