EF Code First数据库连接配置

　　前面几节，使用的都是通过EF Code First创建的新数据库，接下来，将开始使用已存在的数据库。

　　1、使用配置文件设置数据库连接

　　App.config

　　数据库连接字符串的name与Data中NorthwindContext.cs类名相同

<?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=4.3.1.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
  </configSections>
  <connectionStrings>
    <add name="NorthwindContext" connectionString="Data Source=(local); Database=Northwind; User ID=sa; Password=1;" providerName="System.Data.SqlClient"/>
  </connectionStrings>
</configuration>

　　Data中NorthwindContext.cs

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 
 6 using System.Data.Entity;
 7 
 8 using Northwind.Domain.Entities;
 9 using Northwind.Domain.Mapping;
10 
11 namespace Northwind.Data
12 {
13     public class NorthwindContext : DbContext
14     {
15         public DbSet<Category> Categories { get; set; }
16         public DbSet<Product> Products { get; set; }
17         public DbSet<Supplier> Suppliers { get; set; }
18 
19         protected override void OnModelCreating(DbModelBuilder modelBuilder)
20         {
21             modelBuilder.Configurations.Add(new CategoryMap());
22             modelBuilder.Configurations.Add(new ProductMap());
23             modelBuilder.Configurations.Add(new SupplierMap());
24         }
25     }
26 }

　　执行成功后，创建的数据库如下图：

　　2、使用构造函数指定数据库

　　NorthwindContext.cs

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 
 6 using System.Data.Entity;
 7 
 8 using Northwind.Domain.Entities;
 9 using Northwind.Domain.Mapping;
10 
11 namespace Northwind.Data
12 {
13     public class NorthwindContext : DbContext
14     {
15         public NorthwindContext()
16         { }
17 
18         public NorthwindContext(string databaseName)
19             : base(databaseName)
20         {
21 
22         }
23 
24         public DbSet<Category> Categories { get; set; }
25         public DbSet<Product> Products { get; set; }
26         public DbSet<Supplier> Suppliers { get; set; }
27         public DbSet<User> Users { get; set; }
28         public DbSet<Role> Roles { get; set; }
29 
30         protected override void OnModelCreating(DbModelBuilder modelBuilder)
31         {
32             modelBuilder.Configurations.Add(new CategoryMap());
33             modelBuilder.Configurations.Add(new ProductMap());
34             modelBuilder.Configurations.Add(new SupplierMap());
35             modelBuilder.Configurations.Add(new UserMap());
36             modelBuilder.Configurations.Add(new RoleMap());
37         }
38     }
39 }

　　Program.cs

using (NorthwindContext db = new NorthwindContext("Northwind"))
{
}

　　3、使用构造函数指定数据库连接字符串

　　App.config

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <configuration>
 3   <configSections>
 4     <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
 5     <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=4.3.1.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
 6   </configSections>
 7   <connectionStrings>
 8     <add name="NorthwindConnectionString" connectionString="Data Source=(local); Database=Northwind; User ID=sa; Password=1;" providerName="System.Data.SqlClient"/>
 9   </connectionStrings>
10 </configuration>

　　NorthwindContext.cs

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 
 6 using System.Data.Entity;
 7 
 8 using Northwind.Domain.Entities;
 9 using Northwind.Domain.Mapping;
10 
11 namespace Northwind.Data
12 {
13     public class NorthwindContext : DbContext
14     {
15         public NorthwindContext()
16             : base("name=NorthwindConnectionString")
17         { }
18 
19         public DbSet<Category> Categories { get; set; }
20         public DbSet<Product> Products { get; set; }
21         public DbSet<Supplier> Suppliers { get; set; }
22         public DbSet<User> Users { get; set; }
23         public DbSet<Role> Roles { get; set; }
24 
25         protected override void OnModelCreating(DbModelBuilder modelBuilder)
26         {
27             modelBuilder.Configurations.Add(new CategoryMap());
28             modelBuilder.Configurations.Add(new ProductMap());
29             modelBuilder.Configurations.Add(new SupplierMap());
30             modelBuilder.Configurations.Add(new UserMap());
31             modelBuilder.Configurations.Add(new RoleMap());
32         }
33     }
34 }