.NET Framework Developer Center: Comparing LINQ and Its Contemporaries: "It's now been well over thirty years since Codd and friends defined the original relational model. The relational model is now widely accepted and implemented by most commercial database products, but there has yet to be a widely accepted solution to integrating the relational model into general-purpose programming languages used to write applications.
There has been no shortage of attempts to resolve this programming paradox between the relational model and the local programming language. The last two decades, in particular, have seen a flurry of work, ranging from multi-vendor standards committees to individual developers contributing to the open-source community. Despite these efforts, finding the right balance between the power of the relational model and the local idioms of the programming language continues to elude the community at large.
Rather than simply tout the Microsoft LINQ (.NET Language Integrated Query) Project as the right solution, on face value, this paper will present the status quo in this field circa 2005, and then evaluate the LINQ approach relative to this prior art."