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 = "009", Label = "shanghai", Passwd = "123456"});
                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）