Entity Framework Code Firest 连接Postgresql数据库

1、安装Nuget包

　　Npgsq、EntityFramework6.Npgsql

　　

 2、在App.config添加DbContext（数据库上下文）连接字符串

<?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" />
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 --></configSections>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.8" />
    </startup>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="System.Numerics.Vectors" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-4.1.4.0" newVersion="4.1.4.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Runtime.CompilerServices.Unsafe" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-4.0.5.0" newVersion="4.0.5.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Buffers" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-4.0.3.0" newVersion="4.0.3.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Threading.Tasks.Extensions" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-4.2.0.1" newVersion="4.2.0.1" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.ValueTuple" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-4.0.3.0" newVersion="4.0.3.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Npgsql" publicKeyToken="5d8b90d52f46fda7" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-4.1.3.1" newVersion="4.1.3.1" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
  <entityFramework>
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
      <provider invariantName="Npgsql" type="Npgsql.NpgsqlServices, EntityFramework6.Npgsql" />
    </providers>
    <defaultConnectionFactory type="Npgsql.NpgsqlConnectionFactory, EntityFramework6.Npgsql" />
  </entityFramework>
<system.data>
    <DbProviderFactories>
      <remove invariant="Npgsql" />
      <add name="Npgsql Provider" invariant="Npgsql" description=".NET Framework Data Provider for PostgreSQL" type="Npgsql.NpgsqlFactory, Npgsql, Version=4.1.3.0, Culture=neutral, PublicKeyToken=5d8b90d52f46fda7" />
    </DbProviderFactories>
  </system.data>
  <connectionStrings>
    <add name="DataBase" connectionString="server=192.168.0.0;port=8080;Database=Test;uid=user;pwd=123456" providerName="Npgsql" />
  </connectionStrings>
</configuration>

　　server：主机IP、port：端口、Database：数据库名、uid：用户名、pwd=密码

 3、新建一个实体类，用来接收数据库对应的表数据

 public class Cabinets
    {
        public int Id { get; set; }
        public string Address { get; set; }
    }

4、注册数据库上下文

    public class EfDbContext : DbContext
    {
        public EfDbContext(): base("name=DataBase")
        {
        }
        public virtual DbSet<Cabinets> Cabinets { get; set; }
    }

5、在主入口Main方法中实现

 static void Main(string[] args)
        {
            try
            {
                EfDbContext myDatabase = new EfDbContext();

                var list = from s in myDatabase.Cabinets
                           select s;
                foreach (var item in list)
                {
                    Console.WriteLine(item.Id);
                }

                Console.ReadKey();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex);
                Console.ReadKey();
            }
          
        }

　　最后运行出现An error occurred while executing the command definition. See the inner exception for details.的问题

　　解决办法：在实体类中上面加上[Table("Cabinets", Schema = "public")]