ASP.NET3.5网站开发项目实战 教学课件 作者 龚赤兵任务4 LINQ to SQL应用.ppt

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1、任务4LINQtoSQL应用实训1——LINQtoSQL的基本应用实训2——延迟加载实训3——数据修改实训4——存储过程7/22/20211实训1——LINQtoSQL的基本应用创建实体类数据上下文DataContext定义数据表之间的关联基于关联的查询7/22/20212创建实体类7/22/20213创建实体类1:[Table(Name="Customers")]2:publicclassCustomer3:{4:[Column(IsPrimaryKey=true)]5:publicstringCustomerID

2、;6:7:[Column]8:publicstringCity;9:}7/22/20214数据上下文DataContext1:staticvoidMain(string[]args)2:{3:DataContextdb=newDataContext(@"DataSource=.sqlexpress;InitialCatalog=Northwind;IntegratedSecurity=True");4:5:TableCustomers=db.GetTable();6:7:va

3、rq=fromcinCustomerswherec.City=="London"selectc;8:9:foreach(varcustinq)10:Console.WriteLine("id={0},City={1}",cust.CustomerID,cust.City);11:}7/22/20215数据上下文DataContext1:publicpartialclassNorthwind:DataContext2:{3:publicTableCustomers;4:5:publicNorthwi

4、nd(stringconnection):base(connection){}6:}7/22/20216数据上下文DataContext1:staticvoidMain(string[]args)2:{3:Northwinddb=newNorthwind(@"DataSource=.sqlexpress;InitialCatalog=Northwind;IntegratedSecurity=True");4:5:varCustomers=db.Customers;6:7:varq=fromcinCustomersw

5、herec.City=="London"selectc;8:9:foreach(varcustinq)10:Console.WriteLine("id={0},City={1}",cust.CustomerID,cust.City);11:}7/22/20217定义数据表之间的关联1:[Table(Name="Customers")]2:publicclassCustomer3:{4:[Column(IsPrimaryKey=true)]5:publicstringCustomerID;6:7:[Column]8:p

6、ublicstringCity;9:10:privateEntitySet_Orders;11:12:[Association(Storage="_Orders",OtherKey="CustomerID")]13:publicEntitySetOrders14:{15:get{returnthis._Orders;}16:set{this._Orders.Assign(value);}17:}18:}19:7/22/20218定义数据表之间的关联20:[Table(Name="Order

7、s")]21:publicclassOrder22:{23:[Column(IsPrimaryKey=true)]24:publicintOrderID;25:26:[Column]27:publicstringCustomerID;28:29:privateEntityRef_Customer;30:31:[Association(Storage="_Customer",ThisKey="CustomerID")]32:publicCustomerCustomer33:{34:get{retur

8、nthis._Customer.Entity;}35:set{this._Customer.Entity=value;}36:}37:}7/22/20219基于关联的查询1:staticvoidMain(string[]args)2:{3:Northwinddb=newNorthwind(@"DataSource=.sqlexpress;In