Dr. Dobb's Journal - December 2008 - (Page 31) d12espo_p5db 10/10/08 9:54 AM Page 31 [Column(Storage="_CustomerID", DbType="NChar(5) NOT NULL", CanBeNull=false, IsPrimaryKey=true)] Listing One [Table(Name="dbo.Customers")] public partial class Customer : INotifyPropertyChanging, INotifyPropertyChanged { [Column(Storage="_CustomerID", DbType="NChar(5) NOT NULL", CanBeNull=false, IsPrimaryKey=true)] public string CustomerID { get { return this._CustomerID; } set { if ((this._CustomerID != value)) { this.OnCustomerIDChanging(value); this.SendPropertyChanging(); this._CustomerID = value; this.SendPropertyChanged("CustomerID"); this.OnCustomerIDChanged(); } } } : [Association(Name="Customer_Order", Storage="_Orders", OtherKey="CustomerID")] public EntitySet Orders { get { return this._Orders; } set { this._Orders.Assign(value); } } } The Column attribute dictates that the property has to be serialized back to the database table when an instance of the class is made persistent. Likewise, the property has to be initialized with persistent data when an instance of the class is built from a data query. Any class in the LINQ-to-SQL object model doesn’t show off any Save or Load methods for I/O operations. To access the results of a query, you just write a LINQ query: NorthwindDataContext context = new NorthwindDataContext(); var data = from customer in context.Customers where customer.Country == "USA" select customer; The data context object is the entry point in the LINQ-to-SQL engine. The class is automatically generated by the Visual Studio 2008 wizard as a specialization of a system- provided DataContext class. The data context is the means through which developers can run queries and updates against the database. Apparently, the preceding query targets an in-memory object model and has no relationship to the T-SQL language and SQL Server. Some T-SQL code, however, is generated under-the-hood and executed against the database connection associated with the data context. The aforementioned LINQ code evaluates to the following T-SQL: SELECT * FROM customers WHERE country="USA" December 2008 l www.ddj.com l Dr. Dobb’s Journal 31 http://www.codejock.com http://www.codejock.com http://www.ddj.com
Table of Contents Feed for the Digital Edition of Dr. Dobb's Journal - December 2008 Dr. Dobb's Journal - December 2008 Contents Friday Night Fish Fry Alia Vox Developer Diaries Conversations The Man Who Sold the Sky Performance on Rails LINQ-to-SQL and T-SQL A Remote Java RMI Registry Beyond B-Trees File Descriptors and Multithreaded Programs Effective Concurrency The Agile Edge Swaine's Flames Dr. Dobb's Journal - December 2008 Dr. Dobb's Journal - December 2008 - Dr. Dobb's Journal - December 2008 (Page Cover1) Dr. Dobb's Journal - December 2008 - Dr. Dobb's Journal - December 2008 (Page Cover2) Dr. Dobb's Journal - December 2008 - Dr. Dobb's Journal - December 2008 (Page 1) Dr. Dobb's Journal - December 2008 - Dr. Dobb's Journal - December 2008 (Page 2) Dr. Dobb's Journal - December 2008 - Dr. Dobb's Journal - December 2008 (Page 3) Dr. Dobb's Journal - December 2008 - Contents (Page 4) Dr. Dobb's Journal - December 2008 - Contents (Page 5) Dr. Dobb's Journal - December 2008 - Friday Night Fish Fry (Page 6) Dr. Dobb's Journal - December 2008 - Friday Night Fish Fry (Page 7) Dr. Dobb's Journal - December 2008 - Friday Night Fish Fry (Page 8) Dr. Dobb's Journal - December 2008 - Friday Night Fish Fry (Page 9) Dr. Dobb's Journal - December 2008 - Alia Vox (Page 10) Dr. Dobb's Journal - December 2008 - Alia Vox (Page 11) Dr. Dobb's Journal - December 2008 - Developer Diaries (Page 12) Dr. Dobb's Journal - December 2008 - Developer Diaries (Page 13) Dr. Dobb's Journal - December 2008 - Conversations (Page 14) Dr. Dobb's Journal - December 2008 - Conversations (Page 15) Dr. Dobb's Journal - December 2008 - The Man Who Sold the Sky (Page 16) Dr. Dobb's Journal - December 2008 - The Man Who Sold the Sky (Page 17) Dr. Dobb's Journal - December 2008 - The Man Who Sold the Sky (Page 18) Dr. Dobb's Journal - December 2008 - The Man Who Sold the Sky (Page 19) Dr. Dobb's Journal - December 2008 - Performance on Rails (Page 20) Dr. Dobb's Journal - December 2008 - Performance on Rails (Page 21) Dr. Dobb's Journal - December 2008 - Performance on Rails (Page 22) Dr. Dobb's Journal - December 2008 - Performance on Rails (Page 23) Dr. Dobb's Journal - December 2008 - Performance on Rails (Page 24) Dr. Dobb's Journal - December 2008 - Performance on Rails (Page 25) Dr. Dobb's Journal - December 2008 - Performance on Rails (Page 26) Dr. Dobb's Journal - December 2008 - Performance on Rails (Page 27) Dr. Dobb's Journal - December 2008 - Performance on Rails (Page 28) Dr. Dobb's Journal - December 2008 - LINQ-to-SQL and T-SQL (Page 29) Dr. Dobb's Journal - December 2008 - LINQ-to-SQL and T-SQL (Page 30) Dr. Dobb's Journal - December 2008 - LINQ-to-SQL and T-SQL (Page 31) Dr. Dobb's Journal - December 2008 - LINQ-to-SQL and T-SQL (Page 32) Dr. Dobb's Journal - December 2008 - LINQ-to-SQL and T-SQL (Page 33) Dr. Dobb's Journal - December 2008 - LINQ-to-SQL and T-SQL (Page 34) Dr. Dobb's Journal - December 2008 - A Remote Java RMI Registry (Page 35) Dr. Dobb's Journal - December 2008 - A Remote Java RMI Registry (Page 36) Dr. Dobb's Journal - December 2008 - A Remote Java RMI Registry (Page 37) Dr. Dobb's Journal - December 2008 - A Remote Java RMI Registry (Page 38) Dr. Dobb's Journal - December 2008 - A Remote Java RMI Registry (Page 39) Dr. Dobb's Journal - December 2008 - Beyond B-Trees (Page 40) Dr. Dobb's Journal - December 2008 - Beyond B-Trees (Page 41) Dr. Dobb's Journal - December 2008 - File Descriptors and Multithreaded Programs (Page 42) Dr. Dobb's Journal - December 2008 - File Descriptors and Multithreaded Programs (Page 43) Dr. Dobb's Journal - December 2008 - File Descriptors and Multithreaded Programs (Page 44) Dr. Dobb's Journal - December 2008 - File Descriptors and Multithreaded Programs (Page 45) Dr. Dobb's Journal - December 2008 - Effective Concurrency (Page 46) Dr. Dobb's Journal - December 2008 - Effective Concurrency (Page 47) Dr. Dobb's Journal - December 2008 - Effective Concurrency (Page 48) Dr. Dobb's Journal - December 2008 - The Agile Edge (Page 49) Dr. Dobb's Journal - December 2008 - The Agile Edge (Page 50) Dr. Dobb's Journal - December 2008 - The Agile Edge (Page 51) Dr. Dobb's Journal - December 2008 - Swaine's Flames (Page 52) Dr. Dobb's Journal - December 2008 - Swaine's Flames (Page Cover3) Dr. Dobb's Journal - December 2008 - Swaine's Flames (Page Cover4)
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