There are many challenges that have dogged attempts to mesh the DBMS & Object Technology realms for years, critical issues include:
- data access & manipulation impedance arising from Model mismatches between Relational Databases and Object Oriented & Object based Languages
- Record / Data Object Referencing by ID.
The big deal about LINQ has been the singular focus on addressing point 1, in particular.
Here is an architecture diagram that seeks to illustrate the powerful data access and manipulation options that the combination of Linq2RDF and Linked Data deliver:
What may not have been obvious to most in the past, is the fact that Mapping from Object Models to Relational Models wasn't really the solution to the problem at hand. Instead, the mapping should have been the other way around i.e., Relational to Object Model mapping. The emergence of RDF and RDBMS to RDF mapping technology is what makes this age-old headache addressable in very novel ways.