Interesting discussion as it considers how SQL is implemented, what is an abstraction, etc. On the topic of concept-rightness you quickly veer into a language

Interesting discussion as it considers how SQL is implemented, what is an abstraction, etc. On the topic of concept-rightness you quickly veer into a language game. gcc transforms c code into machine code (and may also output error messages, warnings and such). For some, this is not important, and may not be conceptually right. But if you are interested in say the ABI for instance, you do care. On the point of "fundamentalness of abstraction", I interpret it as a measure of how many layers of abstraction (Ab) can be decomposed into the concrete thing of interest. LINQ generates another layer, that of SQL. If it generated an execution plan and sent that to the database optimizer, then I would say it does not generate another layer and would be equal in level of Ab to SQL. But if LINQ can generate SQL that runs on the database, then it is also possible for the database to support LINQ natively. And maybe that was the original intent. However, as it stands today LINQ to SQL costs CPU resources. So in adopting LINQ one of the tradeoffs you are adopting is CPU resources for developer use/benefit of LINQ.