EF Code First增删改查

1、创建项目及下载Entity Framework

　　创建项目如下：

　　项目中安装Entity Framework：

2、数据库连接、实体类及映射文件配置

　　数据库连接配置文件：App.config

<?xml version="1.0" encoding="utf-8"?>

<configuration>

  <configSections>

    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->

    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=4.4.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />

  </configSections>

  <entityFramework>

    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework">

      <parameters>

        <parameter value="Data Source=(local); User ID=sa; Password=1; MultipleActiveResultSets=True" />

      </parameters>

    </defaultConnectionFactory>

  </entityFramework>

</configuration>

　　实体类文件：Province.cs

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;



namespace Northwind.App.Entities

{

    public class Province

    {

        /// <summary>

        /// 省份ID

        /// </summary>

        public Guid ProvinceID { get; set; }



        /// <summary>

        /// 省份编号

        /// </summary>

        public string ProvinceNo { get; set; }



        /// <summary>

        /// 省份名称

        /// </summary>

        public string ProvinceName { get; set; }

    }

}

　　实体类映射文件：ProvinceMap.cs

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;



using System.Data.Entity.ModelConfiguration;

using System.ComponentModel.DataAnnotations.Schema;



using Northwind.App.Entities;



namespace Northwind.App.Mapping

{

    public class ProvinceMap : EntityTypeConfiguration<Province>

    {

        public ProvinceMap()

        {

            // Primary Key

            this.HasKey(t => t.ProvinceID);



            // Properties

            this.Property(t => t.ProvinceNo).HasMaxLength(10);



            this.Property(t => t.ProvinceName).HasMaxLength(50);



            // Table & Column Mappings

            this.ToTable("Province");

            this.Property(t => t.ProvinceID).HasColumnName("ProvinceID").HasDatabaseGeneratedOption(DatabaseGeneratedOption.None);

            this.Property(t => t.ProvinceNo).HasColumnName("ProvinceNo");

            this.Property(t => t.ProvinceName).HasColumnName("ProvinceName");

        }

    }

}

　　数据库操作上下文：NorthwindContext.cs

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;



using System.Data.Entity;



using Northwind.App.Entities;

using Northwind.App.Mapping;



namespace Northwind.App

{

    public class NorthwindContext : DbContext

    {

        public DbSet<Province> Provinces { get; set; }



        protected override void OnModelCreating(DbModelBuilder modelBuilder)

        {

            modelBuilder.Configurations.Add(new ProvinceMap());

        }

    }

}

 　　3、新增

　　代码：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;



using Northwind.App.Entities;



namespace Northwind.App

{

    class Program

    {

        static void Main(string[] args)

        {

            Province province = new Province { ProvinceID = Guid.NewGuid(), ProvinceNo = "100000", ProvinceName = "北京" };

            using (NorthwindContext db = new NorthwindContext())

            {

                db.Provinces.Add(province);

                db.SaveChanges();

            }

        }

    }

}

　　执行的Sql语句：

exec sp_executesql N'insert [dbo].[Province]([ProvinceID], [ProvinceNo], [ProvinceName])

values (@0, @1, @2)

',N'@0 uniqueidentifier,@1 nvarchar(10),@2 nvarchar(50)',@0='F0427980-6CB6-4D5B-91F5-ADE3E676DEA1',@1=N'100000',@2=N'北京'

 　　4、修改

　　代码：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;



using System.Data;



using Northwind.App.Entities;



namespace Northwind.App

{

    class Program

    {

        static void Main(string[] args)

        {

            Province province = new Province { ProvinceID = new Guid("F0427980-6CB6-4D5B-91F5-ADE3E676DEA1"), ProvinceNo = "100000", ProvinceName = "上海" };

            using (NorthwindContext db = new NorthwindContext())

            {

                db.Entry(province).State = EntityState.Modified;

                db.SaveChanges();

            }

        }

    }

}

　　执行的Sql语句：

exec sp_executesql N'update [dbo].[Province]

set [ProvinceNo] = @0, [ProvinceName] = @1

where ([ProvinceID] = @2)

',N'@0 nvarchar(10),@1 nvarchar(50),@2 uniqueidentifier',@0=N'100000',@1=N'上海',@2='F0427980-6CB6-4D5B-91F5-ADE3E676DEA1'

 　　5、删除

　　代码1：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;



using System.Data;



using Northwind.App.Entities;



namespace Northwind.App

{

    class Program

    {

        static void Main(string[] args)

        {



            Province province = new Province { ProvinceID = new Guid("F0427980-6CB6-4D5B-91F5-ADE3E676DEA1") };

            using (NorthwindContext db = new NorthwindContext())

            {

                db.Provinces.Attach(province);

                db.Provinces.Remove(province);

                db.SaveChanges();

            }

        }

    }

}

　　代码2：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;



using System.Data;



using Northwind.App.Entities;



namespace Northwind.App

{

    class Program

    {

        static void Main(string[] args)

        {



            Province province = new Province { ProvinceID = new Guid("F0427980-6CB6-4D5B-91F5-ADE3E676DEA1") };

            using (NorthwindContext db = new NorthwindContext())

            {

                db.Entry(province).State = EntityState.Deleted;

                db.SaveChanges();

            }

        }

    }

}

　　执行的Sql语句：

exec sp_executesql N'delete [dbo].[Province]

where ([ProvinceID] = @0)',N'@0 uniqueidentifier',@0='F0427980-6CB6-4D5B-91F5-ADE3E676DEA1'

 　　6、查询

　　代码：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;



namespace Northwind.App

{

    class Program

    {

        static void Main(string[] args)

        {

            using (NorthwindContext db = new NorthwindContext())

            {

                var expr = from p in db.Provinces

                           select p;



                foreach (var item in expr)

                {

                    Console.WriteLine("{0}-{1}-{2}", item.ProvinceID, item.ProvinceNo, item.ProvinceName);

                }

            }

        }

    }

}

　　执行的Sql语句：

SELECT 

[Extent1].[ProvinceID] AS [ProvinceID], 

[Extent1].[ProvinceNo] AS [ProvinceNo], 

[Extent1].[ProvinceName] AS [ProvinceName]

FROM [dbo].[Province] AS [Extent1]

　　以上全部代码为Entity Framework Code First的基本增删改查的操作，仅为第一步使用Entity Framework Code First操作Sql Server数据库。