If you have defined the relationships in the data context (.dbml), linq has what i would say lazy loading intellisense which gives you a way to do complex query in a simple linq friendly way. Here is an example related to your query: using (dataContext db = new dataContest) { var q = from p in db.ProjectCatergories where p.ProjectCategoryDetails.ProjectContentInfoSamples.ProjectID == "Pr-09" select new { p.projectCategoryName }; } So basically linq joins the tables automatically and that is one of the reasons I believe linq is so powerful! Hope this helps!

Wouldn't the statement be OR? Does he want and? Unless that is what he wants I apologize :)

In Linq2Sql I would have done this: var docs = Documents.Where(c => c.Title.Contains("string") && c.Subject.Contains("string")); Most likely it will work for ef too. Hope it helps!

So basically the linq2sql datacontext and the linq2entities entity model are different. With Visual studio 2008 service pack 1 ships with entity framework. Basically from my understanding the entity framework missed its deadline when visual studio 2008 was getting ready to ship, so they shipped linq2sql instead and waited for sp1 to release the entity framework. You can use one or the other, they both are ORMs shipped with visual studio, its just a matter of preference and what type of application you are developing. To me I prefer linq2sql as I do rapid development, so usually in a larger scale project I would choose the entity framework and there are differences as I stated above and more.

Linq2Sql = SQL Server Linq2Entities(Entity framework) = many relational databases With linq2sql you can only map one class to one table but with linq2entites you can map one class to multiple tables but the biggest thing is linq2sql is designed for rapid development with sql server and entity framework is more built for enterprise level applications hope this helps!