entity-framework - 没有主外键关系的 Entity Framework 代码优先内部连接

Question

我正在使用 Entity Framework 5 code first。我正在尝试在 2 个表之间设置内部连接，但我不确定该怎么做。 2张表没有主键/外键关联，但有一个共同的字段Domain。

tblServer 表:

Server_ID
ServerName
Domain
...
...

tblCommandExecutionServer 表:

ServerListID
ServerName
Domain
...
...

这就是我配置 2 个表以映射到某些实体类的方式:

服务器配置类:

class ServerConfiguration : EntityTypeConfiguration<Server>
{
     internal ServerConfiguration()
     {
          this.ToTable("tblServer");
          this.Property(x => x.Id).HasColumnName("Server_ID");
          this.Property(x => x.Name).HasColumnName("ServerName");
     }
}

CommandExecutionServerConfiguration 类:

class CommandExecutionServerConfiguration : EntityTypeConfiguration<CommandExecutionServer>
{
     internal CommandExecutionServerConfiguration()
     {
          this.ToTable("tblCommandExecutionServer");
          this.Property(x => x.Id).HasColumnName("ServerListID");
          this.Property(x => x.Name).HasColumnName("ServerName");
     }
}

服务器类:

public class Server : IEntity
{
     public int Id { get; set; }

     public string Name { get; set; }

     public string Domain { get; set; }

     public virtual CommandExecutionServer CommandExecutionServer { get; set; }
}

CommandExecutionServer 类:

public class CommandExecutionServer : IEntity
{
     public int Id { get; set; }

     public string Name { get; set; }

     public bool IsActive { get; set; }

     public string Domain { get; set; }

     public virtual Server Server { get; set; }
}

这 2 个表未通过任何列链接。我必须创建以下内部联接但不确定如何创建:

SELECT
     ces.ServerName,
     ws.ServerName,
     ws.Domain
FROM
     tblServer ws
          INNER JOIN tblCommandExecutionServer ces ON ws.Domain = ces.Domain
WHERE
     ws.ServerName = 'my-server-name' AND ces.Active = 1;

我的数据库上下文类:

public DbSet<Server> Servers { get; set; }
public DbSet<CommandExecutionServer> CommandExecutionServers { get; set; }

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
     modelBuilder.Configurations.Add(new ServerConfiguration());
     modelBuilder.Configurations.Add(new CommandExecutionServerConfiguration());
}

然后这就是我目前拥有的，我不知道它应该是什么样子？

public Server FindByServerName(string server, bool isActive, string domain)
{
     return DatabaseContext.Servers
          .SingleOrDefault(entity => entity.Name == server
               && entity.IsActive == isActive);
               //&& entity.Domain == server
}

Answer 1

不支持将这种关系映射到导航属性。关系只能映射到主键之上(至少 EF 必须相信主体实体中定义的列是 PK)。为了支持您在数据库中的关系，Server 中的 Domain 必须是唯一的，但 EF 尚不支持唯一约束。

您只能使用手动 linq join 来执行类似的查询:

var query = from s in context.Server
            join c in context.CommandExecutionServer on s.Domain equals c.Domain
            where s.ServerName == server && c.Active == isActive 
            select new {
                c.ServerName,
                s.ServerName,
                s.Domain
            };