Chapter 7. LINQ to Entities: Basic Concepts and Features

In the previous chapter, we learned new features of C# 3.0 including LINQ. In this chapter and the next, we will explain how to use LINQ to query a database, or in other words, how to use LINQ to Entities in C#. After reading these two chapters we will have a good understanding of LINQ to Entities so that we can rewrite the data access layer of our WCF service with LINQ to Entities, to securely and reliably communicate with the underlying database.

In this chapter, we will cover the basic concepts and features of LINQ to Entities, which include:

• What ORM is

• What LINQ to Entities is

• What LINQ to SQL is

• Comparing LINQ to Entities with LINQ to Objects and LINQ to SQL

• Modeling the Northwind database with LINQ to Entities

• Querying and updating a database with a table

• Deferred execution

• Lazy loading and eager loading

• Joining two tables

• Querying with a view

In the next chapter, we will cover the advanced concepts and features of LINQ to Entities such...