Programming C# 3.0, 5th Edition

Updating Data Using LINQ to SQL

To add or modify data to the database using LINQ, you interact with objects in C#, make your changes, and then tell the DataContext to SubmitChanges, allowing LINQ to take care of the details. This is an extremely object-oriented way to approach data storage. Your code remains strongly typed and yet decoupled from the underlying persistence mechanism.

If you want to add new data to the database, you instantiate a new object and then save it. If you want to modify data already persisted (stored) in the database, you retrieve the object, modify it, and then store it. The key to Example 15-3 is that from a C# perspective, you are interacting with objects and letting LINQ worry about the details of interacting with SQL Server.

Example 15-3. Modifying data using LINQ to SQL

using System; using System.Collections.Generic; using System.Data.Linq; using System.Data.Linq.Mapping; using System.Linq; using System.Text; namespace Modifying_Data_Using_Linq_To_SQL { // Main program public class Tester { static void Main( ) { AddCustomer( ); UpdateCustomer( ); Console.ReadKey( ); } private static void AddCustomer( ) { Console.WriteLine("Adding a new customer..."); AdventureWorksDataContext dc = new AdventureWorksDataContext( ); // Uncomment the statement below to show the // SQL statement generated by LINQ to SQL. // dc.Log = Console.Out; // Add a new customer with address Customer douglas = new Customer( ); douglas.FirstName = "Douglas"; douglas.LastName = "Adams"; ...