Mike Pizzo writes a post about Microsoft's data access strategy that covers a few important things: He takes a different approach on this EF Update post on the ADO.NET team blog.

1) Announces that EF will not make it into the Orcas release but will ship "A few months after the shipment of Orcas, and within the first half of 2008". This plan will allow them to give us more than what they would be able to give us in initial Orcas release. (Also here..)
2) Addresses the LINQ to SQL vs. Entity Framework question, which has been asked quite a lot.

Not much to say about #1 except that I would rather have the first iteration of EF be as strong as possible. I'm in a position where this won't have a big impact on the work that I'm doing (unlike, for example, Scott Bellware who wrote this great post last week about holding off on EF for now), so I'm willing and able to wait it out.

More on #2....

A few months ago, a blog post popped onto the ADO.NET Team blog long enough for me to read it and write about it in my own blog post, but when I returned to get the link to put into my blog post, the post had disappeared.

A few weeks ago, someone asked the question on the LINQ forums and after waiting a few days to see if anyone from Microsoft would answer, I tried to answer it myself. I copied my response into this blog post.

And now finally an official explanation from Mike Pizzo on the ADO.NET team. I truly appreciate getting the perspective from Microsoft since they understand their technology better than I do. This is only a part of the bigger post which is about Microsoft's Data Access strategy.

Mike says explains where to choose LINQ to SQL or Entity Framework. Remember that LINQ to Entities is only one of the ways to leverage Entity Framework. Note that I have added a few comments into his list.

What is the difference between LINQ to SQL and LINQ to Entities? LINQ to SQL supports rapid development of applications that query Microsoft SQL Server databases using objects that map directly to SQL Server schemas. LINQ to Entities supports more flexible mapping of objects to Microsoft SQL Server and other relational databases through extended ADO.NET Data Providers. If you are writing an application that requires any of the following features, you should use the ADO.NET Entity Framework:

o The ability to define more flexible mapping to existing relational schema, for example:
* Mapping a single class to multiple tables
* Mapping to different types of inheritance
* Directly Modeling Many to Many relationships
* Mapping to an arbitrary query against the store

o The ability to query relational stores other than the Microsoft SQL Server family of products.[Julie: Interesting if you have read this or this...]

o The ability to share a model across Replication, Reporting Services, BI, Integration Services, etc.

o A full textual query language [Julie: using Entity SQL, not Linq to Entities]

o The ability to query a conceptual model without materializing results as objects