A lot of people have lingering doubts about whether to use LINQ to SQL for real-world applications, especially since Microsoft has left it to languish in favor of the new version of the Entity Framework slated for release with .NET 4.0 and Visual Studio 2010. Nevertheless, I have a consulting client, Credit Solutions, that uses LINQ to SQL for their line-of-business web application and has had a very favorable experience working with it. In addition you’ll get better performance using LINQ to SQL (we’ll see how EF4 compares when it comes out).

The bottom line is that LINQ to SQL is a perfectly viable alternative when you can guarantee that the database will be Microsoft SQL Server (2000 or later). It has support for POCO (persistence ignorance), stored procedures, lazy loading, and concurrency management, and it works well with SOA (n-tier) architectures.

The question is, "Who is adding new features to LINQ to SQL?" The answer is a product called Plinqo, created by the makers of the code-generation tool, Code Smith. The purpose of Plinqo is to generate LINQ to SQL entities that replace those created when you add a dbml file to a Visual Studio project. In fact, Plinqo will generate the dbml file for you, placing each entity in a separate .cs file under a common folder. Actually, Plinqo creates two files: one for the code-generated entity, and another for your own custom metadata that will not be overwritten by the code-generator (for example, attributes that can drive a dynamic data web site).

While Plinqo generates code that is better organized and easier to read, its power lies in the extensions it provides, such as manager and query classes, a build-in rules engine, audit trail, caching, cloning and detaching entities. It also de-normalizes many-to-many relationships and takes advantage of improvements to the DataContract attributes for .NET 3.5 SP1 (avoiding cyclic references and the need for the "unidirectional" serialization option). In addition, Plinqo will create enums instead of entities for tables with lookup values.

But wait, there’s more! Plinqo has actually enabled batch updates and deletes, eliminating possible round-trips when calling SubmitChanges to process updated entities. Wow, now that is something I had been hoping Microsoft would give us in the next version. But thanks to Plinqo, I won’t have to hold my breath waiting for Microsoft, which has stopped adding new features to LINQ to SQL. Lastly, Plinqo also enables batch queries and the ability to process multiple result sets from stored procedures.

And to top it off, Plinqo has templates to create an ADO.NET Data Services layer that exposes entities via a REST-ful web service. There’s even a quick start template that will create both the service and a dynamic data web client in a matter of seconds.

So before you decide to give up on LINQ to SQL, check out Plinqo to get a fresh option for using LINQ to SQL in real-world applications. They’re even offering a free CodeSmith license if you mention Plinqo in a blog or tweet.