PostgreSQL Entity Framework 自动迁移

1、依次添加NuGet包 EntityFramework、Npgsql、EntityFramework6.Npgsql，会自动生成一些配置文件，不过缺少数据库驱动的配置节点：

   <system.data>
     <DbProviderFactories>
       <!--  注意这里，安装程序包时，这里的配置并不会自动添加  -->
       <remove invariant="Npgsql" />
       <add name="Npgsql" invariant="Npgsql" description=".Net Framework Data Provider for Postgresql" type="Npgsql.NpgsqlFactory, Npgsql" />
     </DbProviderFactories>
   </system.data>
   <connectionStrings>
     <!-- 数据库连接字符串, 主机, 用户, 密码, 数据库 -->
     <add name="mes" connectionString="Server=localhost;Uid=postgres;Password=1234;Database=Mes" providerName="Npgsql"/>
   </connectionStrings>

2、添加测试的数据库模型：

     public class BaseModel
     {
         [Key]
         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
         public long Id { get; set; }
         public string Remark { get; set; }
         public DateTime CreTime { get; set; } = DateTime.Now;
         public bool IsDel { get; set; } = false;
         public DateTime? UpdateTime { get; set; }
     }

     [Table("User")]
     public class User : BaseModel
     {
         public string Account { get; set; }
         public string Label { get; set; }
         public string Passwd { get; set; }
         public long? UpdateUid { get; set; }
     }

     [Table("Order")]
     public class Order: BaseModel
     {
         public string OrderNo { get; set; }
         public decimal Qty { get; set; }
         public string Style { get; set; }
         public string Size { get; set; }
         public string Color { get; set; }
         public DateTime? DeliveryTime { get; set; }
         public string ShipAddress { get; set; }
         public string Phone { get; set; }
         public long? CustomerId { get; set; }

         [ForeignKey("CustomerId")]
         public User Customer { get; set; }
     }

3、数据库上下文：

     public class MesContext:DbContext
     {
         public MesContext():base("name=mes")
         {

         }

         public DbSet<User> Users { get; set; }
         public DbSet<Order> Orders { get; set; }
     }

4、添加自动迁移配置：

     public class MigrationConfig:DbMigrationsConfiguration<MesContext>
     {
         public MigrationConfig()
         {
             AutomaticMigrationsEnabled = true;
             //到生产环境后，注释以下
             AutomaticMigrationDataLossAllowed = true;
         }
     }

5、发布代码时，自动迁移到最新：

             using (var db = new MesContext())
             {
                 new MigrateDatabaseToLatestVersion<MesContext, MigrationConfig>("mes").InitializeDatabase(db);

                 //测试添加User
                 db.Users.Add(new User() {Account = "", Label = "shanghai", Passwd = ""});
                 db.SaveChanges();
             }

6、完整配置文件：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=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
   </configSections>
   <startup>
     <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
   </startup>
   <entityFramework>
     <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
     <providers>
       <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
       <provider invariantName="Npgsql" type="Npgsql.NpgsqlServices, EntityFramework6.Npgsql" />
     </providers>
   </entityFramework>
   <runtime>
     <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
       <dependentAssembly>
         <assemblyIdentity name="Npgsql" publicKeyToken="5d8b90d52f46fda7" culture="neutral" />
         <bindingRedirect oldVersion="0.0.0.0-3.2.5.0" newVersion="3.2.5.0" />
       </dependentAssembly>
     </assemblyBinding>
   </runtime>
   <system.data>
     <DbProviderFactories>
       <!--  注意这里，安装程序包时，这里的配置并不会自动添加  -->
       <remove invariant="Npgsql" />
       <add name="Npgsql" invariant="Npgsql" description=".Net Framework Data Provider for Postgresql" type="Npgsql.NpgsqlFactory, Npgsql" />
     </DbProviderFactories>
   </system.data>
   <connectionStrings>
     <!-- 数据库连接字符串, 主机, 用户, 密码, 数据库 -->
     <add name="mes" connectionString="Server=localhost;Uid=postgres;Password=1234;Database=Mes" providerName="Npgsql"/>
   </connectionStrings>
 </configuration>

7、NuGet配置：packages.config

 <?xml version="1.0" encoding="utf-8"?>
 <packages>
   <package id="EntityFramework" version="6.2.0" targetFramework="net45" />
   <package id="EntityFramework6.Npgsql" version="3.1.1" targetFramework="net45" />
   <package id="Npgsql" version="3.2.5" targetFramework="net45" />
   <package id="System.Threading.Tasks.Extensions" version="4.3.0" targetFramework="net45" />
 </packages>

注：第一次自动迁移前需要手动先创建数据库（Mes）