创建复合密钥实体框架

Question

不久,我想在我的表上创建复合键,保留主键,以提高sql server搜索性能.每当我搜索没有主键的实体(即一串GUID)时,性能问题就会发生在200k数据表上.假设我有3个班级

public class Device{

    public int ID { get; set; } 
    public string UDID { get; set; }
    public string ApplicationKey { get; set; }
    public string PlatformKey { get; set; }

    public ICollection<NotificationMessageDevice> DeviceMessages { get; set; } 
}

public class NotificationMessageDevice { 

    [Column(Order = 0), Key, ForeignKey("NotificationMessage")]
    public int NotificationMessage_ID { get; set; }

    [Column(Order = 1), Key, ForeignKey("Device")]
    public int Device_ID { get; set; }

    public virtual Device Device { get; set; }
    public virtual NotificationMessage NotificationMessage { get; set; }
}

public class NotificationMessage { 

    public int ID { get; set; }
    public string Text { get; set; }
    public DateTime CreateDate { get; set; }
}

        modelBuilder.Entity<Device>().HasKey(t => new { t.ID, t.ApplicationKey, t.PlatformKey, t.UDID });

问题是每当我想使用modelBuilder将ID,UDID,ApplicationKey和PlatformKey定义为复合键时,它会产生以下错误.

NotificationMessageDevice_Device_Target_NotificationMessageDevice_Device_Source ::关系约束中的从属角色和主要角色中的属性数必须相同

我认为问题是因为NotificationMessageDevice上的导航属性无法识别Device表上的主键.我该如何解决这个问题？除此之外,如果您分享改善Entity框架搜索性能的经验,我将很高兴.通常,只要我使用没有主键的First方法,就会出现性能问题.

Answer 1

如果Device表具有复合主键,则NotificationMessageDevice表上需要相同的复合外键.SQL如何在没有完整主键的情况下找到Device？此外,您应该使这些字段成为NotificationMessageDevice表主键的一部分.否则您无法保证主键是唯一的:

public class NotificationMessageDevice
{
    [Column(Order = 0), Key, ForeignKey("NotificationMessage")]
    public int NotificationMessage_ID { get; set; }

    [Column(Order = 1), Key, ForeignKey("Device")]
    public int Device_ID { get; set; }
    [Column(Order = 2), Key, ForeignKey("Device")]
    public string Device_UDID { get; set; }
    [Column(Order = 3), Key, ForeignKey("Device")]
    public string Device_ApplicationKey { get; set; }

    public virtual Device Device { get; set; }
    public virtual NotificationMessage NotificationMessage { get; set; }
}