EF6使用Code First模式连接Postgresql数据库

1. 通过Nuget 安装 Npgsql  

2. 通过Nuget 安装 EntityFramework6.Npgsql

3. 创建一个包含空的Code Fisrt模型的项目。 

4.  创建一个SysUser.cs的模型： （Table特性中Schema）

namespace YFrame.Model.EF

{

    // EF会把dbo作为默认的数据库schema, 而Postegres是public，
    // 解决方案 
    // 1. [Table("SysUser", Schema = "public")] 特性
    // 2. 在PostgreSQL中建立完数据库，再创建个名字为dbo的schema，所有的数据表和其他对象都建立在这个schema下
    [Table("SysUser", Schema = "public")]
    public class SysUser
    {
        public int Id { get; set; }
        public string UserName { get; set; }
        public string Password { get; set; }
    }
}

5. 修改YFrameContext.cs文件

public class YFrameContext : DbContext
 {
        public YFrameContext()
            : base("name=YFrameContext")
        {
        }

        public virtual DbSet<SysUser> SysUser { get; set; }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {   
            // 移除复数形式
            modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
        }
    }

6. 修改 App.config

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  
  <configSections>
    <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=v4.5.2" />
  </startup>
  <connectionStrings>
    <add name="YFrameContext" connectionString="server=localhost;User Id=postgres;password=postgres;database=NAPP" providerName="Npgsql" />
  </connectionStrings>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
      <parameters>
        <parameter value="v13.0" />
      </parameters>
    </defaultConnectionFactory>
    <providers>
      <provider invariantName="Npgsql" type="Npgsql.NpgsqlServices, EntityFramework6.Npgsql" />
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
  </entityFramework>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Npgsql" publicKeyToken="5d8b90d52f46fda7" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-3.1.0.0" newVersion="3.1.0.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
  <system.data>
    <DbProviderFactories>
      <remove invariant="Npgsql"></remove>
      <add name="Npgsql Data Provider" invariant="Npgsql" description=".Net Framework Data Provider for Postgresql Server" type="Npgsql.NpgsqlFactory, Npgsql" />
      <add name="dotConnect for PostgreSQL" invariant="Devart.Data.PostgreSql" description="Devart dotConnect for PostgreSQL" type="Devart.Data.PostgreSql.PgSqlProviderFactory, Devart.Data.PostgreSql, Version= 7.7.804.0, Culture=neutral, PublicKeyToken=09af7300eec23701" />
    </DbProviderFactories>
  </system.data>

</configuration>

7. 创建YFrameInitializer.cs, 用来处理化数据库。

namespace YFrame.Model.EF

{
    public class YFrameInitializer : DropCreateDatabaseIfModelChanges<YFrameContext>
    {
        protected override void Seed(YFrameContext context)
        {
            new List<SysUser> {
                new SysUser { Id = 10, UserName = "yang"},
                new SysUser { Id = 11, UserName = "chao"}
            }.ForEach(a => context.SysUser.Add(a));

            context.SaveChanges();
        }
    }
}

8. 测试是否连接成功。

namespace ConsoleTest
{
    class Program
    {
        static void Main(string[] args)
        {
            // 初始化数据库
            Database.SetInitializer<YFrameContext>(new YFrameInitializer());

            using (var db = new YFrameContext())
            {
                SysUser user = new SysUser { Id = 1, UserName = "zhao" };
                db.SysUser.Add(user);
                db.SaveChanges();
                var list = db.SysUser;
                foreach (var item in list)
                {
                    Console.WriteLine(item.Id + item.UserName);
                }
            }
            Console.ReadLine();
        }
    }
}