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Chan Ming ManC# MVPhttp://chanmingman.spaces.live.comLevel 200

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Chan Ming ManC# MVPhttp://chanmingman.spaces.live.comLevel 200

CRUD Using LINQ (Language Integrated Query)

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Agenda

The object model challenges the relational model

What is LINQ?

LINQ to SQL

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Helpful Experience

Visual Studio 2008 C# Express

SQL Server 2005

ADO.NET

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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#.

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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

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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

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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?

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LINQ

Query, Set, and Transform Operations for .NET

Makes querying data a core programming concept

Works with all types and shapes of dataRelational databasesXMLPlain old Objects

Works with all .NET languagesNew VB and C# have integrated language support

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What is LINQ?

Strongly-typedBenefits from IntelliSense

Language INtegrated Queries

Collections of objectsRelational dataXML

Queries integrated with code (C#/VB)

Unified Querying

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LINQ Enabled Data Sources

LINQ enabled ADO.NET

LINQ Architecture

LINQ to

Entities

LINQ To

SQL

LINQ to

XML

C# 3.0 VB 9.0 Others…

LINQ To

Dataset

LINQ To

Objects

XMLObjects Relational Data

.NET Language-Integrated Query (LINQ)

11©2008 Pavel Yosifovich

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Where is LINQ to SQL in MVC?

Model

ControllerView

LINQ To

SQL

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LINQ to SQL

Application

SQL Server

LINQ to SQL

from c in db.Customerswhere c.City == "London"select c.CompanyName

LINQ Query

SQL Query

SELECT CompanyNameFROM CustWHERE City = 'London'

Rows

Objects SubmitChanges()

DML or Stored Procedures

db.Customers.Add(c1);c2.City = “Seattle";db.Customers.Remove(c3);

INSERT INTO Customers…UPDATE Customers …DELETE FROM Customers …

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LINQ to SQL fully support CRUD

C = Create = InsertR = Read = SelectU = UpdateD = Delete

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CreateLINQ

var newCustomer = new Customer {CustomerID = "DLEAP",CompanyName = "DevLeap",Country = "Italy" };db.Customers.InsertOnSubmit(newCustomer);

INSERT INTO [Customers](CustomerID, CompanyName, ...)VALUES("DLEAP", "DevLeap", ...)

SQL

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Read

var query =from c in Customerswhere c.Country == "USA"&& c.State == "WA"select new {c.CustomerID, c.CompanyName, c.City };

SELECT CustomerID, CompanyName, CityFROM CustomersWHERE Country = 'USA'AND Region = 'WA'

LINQ

SQL

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Update

Customer cust = db.Customers.Single(p => p.CustomerID == 11111);cust.LastName = “Thomas ";db.SubmitChanges();

UPDATE Customer LastName = “Thomas "SET WHERE CustomerID == 11111

SQL

LINQ

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Delete

var oldDetail = db.Order_Details.Single(od => od.OrderID == 10422&& od.ProductID == 26);db.Order_Details.DeleteOnSubmit(oldDetail);

DELETE FROM [dbo].[Order Details]WHERE [OrderID] = 10422 AND [ProductID] = 26 AND ...

SQL

LINQ

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Demo …

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Resources - LINQ

MSDN Developer Centerhttp://msdn2.microsoft.com/en-us/netframework/aa904594.aspx

LINQ Forumhttp://forums.microsoft.com/msdn/showforum.aspx?forumid=123

Channel9 Linq Videoshttp://channel9.msdn.com/tags/linq

BlogsScott 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 HOLC# 3.0 Enhancements & LINQ (English)

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© 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.