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.NET:Entity Framework 6.1笔记
EF6越来越完善，跟主流的Hibernate等ORM框架越来越接近了，先看下Entity类的定义：
using System;using System.Collections.Generic;using System.ComponentModel.DataAnnotations;using System.ComponentModel.DataAnnotations.Schema;namespace EFSample.Model{ [Table("T_ORDER")] public class Order { [Key] [DatabaseGenerated(DatabaseGeneratedOption.Identity)] public int ID { set; get; } [StringLength(50)] [Column("CUSTOMER_NAME")] public String CustomerName { set; get; } [Column("AMOUNT")] public decimal Amount { set; get; } public virtual ICollection<OrderItem> OrderItems { set; get; } }}
1 using System; 2 using System.ComponentModel.DataAnnotations; 3 using System.ComponentModel.DataAnnotations.Schema; 4 5 namespace EFSample.Model 6 { 7 [Table("T_ORDER_ITEM")] 8 public class OrderItem 9 {10 [Key]11 [DatabaseGenerated(DatabaseGeneratedOption.Identity)]12 public int ID { set; get; }13 14 [ForeignKey("Order")]15 [Column("ORDER_ID")]16 public int OrderID { set; get; }17 18 [StringLength(50)]19 [Column("PRODUCT_NAME")]20 public String ProductName { set; get; }21 22 [Column("PRICE")]23 public Decimal Price { set; get; }24 25 [Column("QUANTITY")]26 public int Quantity { set; get; }27 28 public virtual Order Order { set; get; }29 30 31 }32 }
光看Attribute，已经跟Hibernate的Annotation很相似了。
配置文件：
1 <?xml version="1.0" encoding="utf-8"?> 2 <configuration> 3 <configSections> 4 <section name="entityFramework" 5 type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" /> 6 </configSections> 7 8 <entityFramework> 9 <contexts>10 <context type="EFSample.DAL.OrderContext, EFSample" disableDatabaseInitialization="false">11 <databaseInitializer type="EFSample.DAL.OrderInitializer, EFSample" />12 </context>13 </contexts>14 <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">15 <parameters>16 <parameter value="v11.0" />17 </parameters>18 </defaultConnectionFactory>19 <providers>20 <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />21 </providers>22 </entityFramework>23 24 <startup>25 <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5.1" />26 </startup>27 28 <connectionStrings>29 <!--连接字符串，使用SQLSERVER LocalDb-->30 <add name="MyConn" connectionString="Data Source=(LocalDb)\v11.0;Initial Catalog=OrderDatabase;Integrated Security=SSPI;" providerName="System.Data.SqlClient" />31 </connectionStrings>32 33 </configuration>
注：LocalDb在开发阶段很方便，但是试用中有一个小问题，如果把生成的mdf物理文件删除后，再次运行总是报错(不知道是不是个别现象)，只能把Initial Catalog=OrderDatabase中的文件名改成其它名称（比如：Catalog=OrderDb），才能正常运行。
此外，NuGet Package Manager工具搞得象java的maven一样，可以自动联机下载所需的依赖项，Tools->NuGet Package Manager
输入
Install -Package EntityFramework
就能自动向project添加相关的dll引用
DbContext
1 using EFSample.Model; 2 using System.Data.Entity; 3 using System.Data.Entity.ModelConfiguration.Conventions; 4 5 namespace EFSample.DAL 6 { 7 public class OrderContext:DbContext 8 { 9 public OrderContext() : base("MyConn") { }10 11 public DbSet<Order> Orders { set; get; }12 13 public DbSet<OrderItem> OrderItems { set; get; }14 15 protected override void OnModelCreating(DbModelBuilder modelBuilder)16 {17 modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();18 }19 }20 }
示例代码：
1 using EFSample.DAL; 2 using EFSample.Model; 3 using System; 4 using System.Collections.Generic; 5 using System.Linq; 6 7 namespace EFSample 8 { 9 class Program10 {11 static void Main(string[] args)12 {13 using (var db = new OrderContext())14 {15 16 //直接执行Sql语句17 db.Database.ExecuteSqlCommand("delete from t_order");18 19 var orders = new List<Order>(){ 20 new Order{ CustomerName="jimmy.yang",Amount=200, OrderItems=new List<OrderItem>(){21 new OrderItem(){ Price=10, Quantity=20, ProductName="Mobile"}22 }},23 new Order{ CustomerName="杨俊明",Amount=300, OrderItems=new List<OrderItem>(){24 new OrderItem(){ Price=15, Quantity=20, ProductName="架构之美"}25 }}};26 27 //批量添加记录28 db.Orders.AddRange(orders);29 30 //提交到db31 db.SaveChanges(); 32 33 //查询34 var query = db.Orders.Where(c => c.CustomerName == "Jimmy.yang").AsQueryable();35 36 //输出Sql语句37 Console.WriteLine(query.ToString());38 39 List<Order> orderEntities = query.ToList();40 41 foreach (var order in orderEntities)42 {43 Console.WriteLine(String.Format("ID:{0}/CustomerName:{1}/Amount:{2}/ItemCount:{3}", order.ID, order.CustomerName, order.Amount,order.OrderItems.Count));44 }45 }46 47 Console.WriteLine("ok!");48 Console.Read();49 }50 }51 }
输出：
SELECT
[Extent1].[ID] AS [ID],
[Extent1].[CUSTOMER_NAME] AS [CUSTOMER_NAME],
[Extent1].[AMOUNT] AS [AMOUNT]
FROM [dbo].[T_ORDER] AS [Extent1]
WHERE N‘Jimmy.yang‘ = [Extent1].[CUSTOMER_NAME]
ID:9/CustomerName:jimmy.yang/Amount:200/ItemCount:1
ok!
.NET:Entity Framework 6.1笔记
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