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.Data12 {13     public class NorthwindContext : DbContext14     {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.Data12 {13     public class NorthwindContext : DbContext14     {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.Data12 {13     public class NorthwindContext : DbContext14     {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 }