L INQ: Language Integrated Query

Hands-on Lab

November 2007

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Contents

Lab 1: LINQ Project: Unified Language Features for Object and Relational Queries 1

Lab Objective 1

Exercise 1 –LINQ for In-Memory Collections 2

Task 1 – Creating the “LINQ Overview” Solution 2

Task 2 – Querying a Generic List of Integers 2

Task 3 – Querying Structured Types 4

Exercise 2 – LINQ to XML: LINQ for XML documents 6

Task 1 – Adding LINQ to XML Support 6

Task 2 – Querying by Reading in an XML File 6

Task 3 – Querying an XML File 7

Task 4 – Transforming XML Output 8

Exercise 3 – LINQ to DataSet: LINQ for DataSet Objects 9

Task 1 – Adding DataSet Support 9

Task 2 – Creating a DataSet – Add Designer File 10

Task 3 – Creating a DataSet – Using the Designer 10

Task 4 – Querying a DataSet 10

Exercise 4 – LINQ to SQL: LINQ for Connected Databases 11

Task 1 – Adding LINQ to SQL Support 12

Task 2 – Creating Object Mapping – Creating an Object and Providing Attributes 12

Task 3 – Creating Object Mapping – Using the Designer – Add Designer File 13

Task 4 – Creating Object Mapping – Using the Designer – Create the Object View 13

Task 5 – Querying using Expressions 14

Task 6 – Modifying Database Data 15

Task 7 – Calling Stored Procedures 17

Task 8 – Expanding Query Expressions 17

Exercise 5 – Understanding the Standard Query Operators [Optional] 19

Task 1 – Querying using the Standard Query Operators 19

Task 2 – Working with the Select Operator 20

Task 3 – Working with the Where Operator 22

Task 4 – Working with the Count Operator 23

Task 5 – Working with the Min, Max, Sum, and Average Operators 24

Task 6 – Working with the All and Any operators 25

Task 7 – Working with the ToArray and ToList Operators 26

Lab Summary 28

Lab 1: linq Project: Unified Language Features for Object and Relational Queries

This lab provides an introduction to the LINQ Project. The language integrated query framework for .NET (“LINQ”) is a set of language extensions to C# and Visual Basic and a unified programming model that extends the .NET Framework to offer integrated querying for objects, databases, and XML.

In this lab, you will see how LINQ features can be used against in-memory collections, XML documents, and connected databases. The lab ends with an optional exercise that looks at the various standard query operators available for data manipulation and extraction.

This lab makes extensive use of new language features provided in C# 3.0. When first introduced they are pointed out; however for a more in depth understanding of how these features work, refer to the C# 3.0 Language Specification Hands On Lab.

Lab Objective

Estimated time to complete this lab: 60 minutes

The objective of this lab is to provide a clear understanding of the LINQ project. You will see how data manipulation can occur on objects in memory, XML files, datasets, and relational databases. The new LINQ APIs benefit from IntelliSense™ and full compile-time checking without resorting to string-based queries. This lab touches on basic LINQ technologies, along with database-specific LINQ to SQL, XML-specific LINQ to XML, and dataset-specific LINQ to DataSets. A brief look at query operators is also included.

This lab uses the Northwind database and consists of the following exercises:

LINQ to Objects: LINQ for In-Memory Collections LINQ to XML: LINQ for XML Documents LINQ to DataSets: LINQ for Dataset Objects LINQ to SQL: LINQ for Connected DatabasesUnderstanding the Standard Query Operators [Optional]