Dev-In-Town

1. devInTown Chan Ming Man C# MVP http://chanmingman.spaces.live.com Level 200

2. devInTown CRUD Using LINQ (Language Integrated Query) Chan Ming Man C# MVP http://chanmingman.spaces.live.com Level 200

3. Agenda The object model challenges the relational model What is LINQ? LINQ to SQL

4. Helpful Experience Visual Studio 2008 C# Express SQL Server 2005 ADO.NET

5. The object model challenges the relational model The relational model has been fantastically successful in a wide variety of application areas. However, it is not problem free. The problems have been made more visible by the rise in popularity of object-oriented programming languages such as C++, Java, and C#.

6. Data…its our job Querying and manipulating data has always been a fundamental part of our jobs as programmers Data formats change, but core needs are the same

7. Data Access(DBASE circa 1980s) USE empl REPLACE ALL salary WITH (salary * 1.1) FOR supervises > 0 LIST ALL fname, lname, salary FOR Supervises > 0 Data querying and manipulation a core part of the programming model experience Certainly had limitations, but it sure was useful

8. But Challenges Still Remain… How to retrieve non-relational data? XML, RSS, Web Services, REST, AD, Files, etc. How to interact with plain old objects? How do you interact and query custom domain models? How to enable rich data shaping & transformations? Support flexible query composition (that is fast!) How to enable clean code in both a strongly typed and dynamic language world?

9. LINQ Query, Set, and Transform Operations for .NET Makes querying data a core programming concept Works with all types and shapes of data Relational databases XML Plain old Objects Works with all .NET languages New VB and C# have integrated language support

10. Queries integrated with code (C#/VB) What is LINQ? Strongly-typed Benefits from IntelliSense Collections of objects Relational data XML Unified Querying Language INtegrated Queries

11. LINQ Architecture C# 3.0 VB 9.0 Others… .NET Language-Integrated Query (LINQ) LINQ Enabled Data Sources LINQ enabled ADO.NET LINQ to Entities LINQ To SQL LINQ to XML LINQ To Dataset LINQ To Objects XML Objects Relational Data 11 ©2008 Pavel Yosifovich

12. Where is LINQ to SQL in MVC? Model LINQ To SQL Controller View

13. LINQ to SQL Application from c in db.Customers where c.City == "London" select c.CompanyName db.Customers.Add(c1); c2.City = “Seattle"; db.Customers.Remove(c3); LINQ Query Objects SubmitChanges() LINQ to SQL SQL Query Rows DML or Stored Procedures SELECT CompanyName FROM Cust WHERE City = 'London' INSERT INTO Customers… UPDATE Customers …DELETE FROM Customers … SQL Server

14. LINQ to SQL fully support CRUD C = Create = Insert R = Read = Select U = Update D = Delete

15. Create LINQ varnewCustomer = new Customer { CustomerID = "DLEAP", CompanyName = "DevLeap", Country = "Italy" }; db.Customers.InsertOnSubmit(newCustomer); SQL INSERT INTO [Customers](CustomerID, CompanyName, ...) VALUES("DLEAP", "DevLeap", ...)

16. Read LINQ var query = from c in Customers where c.Country == "USA" && c.State == "WA" select new {c.CustomerID, c.CompanyName, c.City }; SQL SELECT CustomerID, CompanyName, City FROM Customers WHERE Country = 'USA' AND Region = 'WA'

17. Update LINQ Customer cust = db.Customers.Single(p => p.CustomerID == 11111); cust.LastName = “Thomas "; db.SubmitChanges(); SQL UPDATE Customer LastName = “Thomas " SET WHERE CustomerID == 11111

18. Delete LINQ varoldDetail = db.Order_Details.Single( od => od.OrderID == 10422 && od.ProductID == 26); db.Order_Details.DeleteOnSubmit(oldDetail); SQL DELETE FROM [dbo].[Order Details] WHERE [OrderID] = 10422 AND [ProductID] = 26 AND ...

19. Demo …

20. Resources - LINQ MSDN Developer Center http://msdn2.microsoft.com/en-us/netframework/aa904594.aspx LINQ Forum http://forums.microsoft.com/msdn/showforum.aspx?forumid=123 Channel9 Linq Videos http://channel9.msdn.com/tags/linq Blogs Scott Guthrie http://weblogs.asp.net/scottgu/archive/2007/04/21/new-orcas-language-feature-query-syntax.aspx Charlie Calvert http://blogs.msdn.com/charlie/archive/2006/10/05/Links-to-LINQ.aspx LINQ HOL C# 3.0 Enhancements & LINQ (English)

21. © 2008 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.