Chapter 1. Introducing LINQ

Software is simple. It boils down to two things: code and data. Writing software is not so simple, and one of the major activities it involves is writing code that deals with data.

To write code, we can choose from a variety of programming languages. The selected language for an application may depend on the business context, on developer preferences, on the development team’s skills, on the operating system, or on company policy.

Whatever language you end up with, at some point you will have to deal with data. This data can be in files on a disk, tables in a database, or XML documents coming from the Web, or often you have to deal with a combination of all of these. Ultimately, managing data is a requirement for every software project you’ll work on.

Given that dealing with data is such a common task for developers, we would expect rich software development platforms like the .NET Framework to provide an easy way to do it. .NET does provide wide support for working with data. You will see, however, that something had yet to be achieved: deeper language and data integration. This is where LINQ to Objects, LINQ to XML, and LINQ to SQL fit in.

1.1. What is LINQ?

1.2. Why do we need LINQ?

1.3. Design goals and origins of LINQ

1.4. First steps with LINQ to Objects: Querying collections in memory

1.5. First steps with LINQ to XML: Querying XML documents

1.6. First steps with LINQ to SQL: Querying relational databases

1.7. Summary