Question

我正在尝试使用代码优先创建数据库项目和数据注释，但我对架构有一些疑问。我不确定我的关系模式是否有意义，在SQL中是否正确并且可能在EF中实现。如何从一个子表到两个parrent表之一建立条件关系。在我的ProcessRelation表中，我将保存两个关系。 JobBusinessArea - Estimates和jobBussinesArea - PriceList。我希望它能有所作为。感谢您提供任何帮助和建议。

[Table("ProcessRelation")]
    public class ProcessRelation
    {
        [Key, Column("AreaId", Order = 0)]
        public int AreaId { get; set; }
        [Key, Column("ModId", Order = 1)]
        public int ModId { get; set; }
    [Key, Column("PriceSourceTypeId", Order = 2)]
        public int PriceSourceTypeId { get; set; }
        public int CrtUsrnm { get; set; }
        public DateTime CrtTmstmp { get; set; }
        public int LcUsrnm { get; set; }
        public DateTime LcTmstmp { get; set; }

        [ForeignKey("PriceSourceTypeId")]
        public virtual BillingProjectCode PriceSourceTypeCode { get; set; }
        [ForeignKey("AreaId")]
        public virtual JobBusinessArea JobBusinessArea { get; set; }

        //TODO:
        //Depending on the PriceSourceTypeId i would like create reference to PriceListProcessMod Table 
    //or EstimateProcessMod Table
        //[ForeignKey("ModId")]
        //public virtual PriceListProcessMod PriceListProcessMod { get; set; }
        // or
        //public virtual EstimateProcessMod EstimateProcessMod { get; set; }
    }


[Table("PriceListProcessMod")]
    public class PriceListProcessMod
    {
        [Key, Column("ModId", Order = 0)]
        public int ModId { get; set; }
        public int ProcessId { get; set; }
        public int Quantity { get; set; }
        public bool IsIncluded { get; set; }
        public int CrtUsrnm { get; set; }
        public DateTime CrtTmstmp { get; set; }
        public int LcUsrnm { get; set; }
        public DateTime LcTmstmp { get; set; }
        public decimal? CommisionPercentage { get; set; }
        public bool? IsProportionalyFixed { get; set; }
        [ForeignKey("ProcessId")]
        public virtual PriceListProcess PriceListProcess { get; set; }
    }

[Table("EstimateProcessMod")]
    public class EstimateProcessMod
    {
        [Key, Column("ModId", Order = 0)]
        public int ModId { get; set; }
        public int? SplitId { get; set; }
        public int ProcessId { get; set; }
        public int Quantity { get; set; }
        public bool IsIncluded { get; set; }
        public int CrtUsrnm { get; set; }
        public DateTime CrtTmstmp { get; set; }
        public int LcUsrnm { get; set; }
        public DateTime LcTmstmp { get; set; }
        public decimal? CommisionPercentage { get; set; }
        public bool? IsProportionalyFixed { get; set; }
        [ForeignKey("ProcessId")]
        public virtual EstimateProcess EstimateProcess{ get; set; }
    }

 [Table("JobBusinessArea")]
    public class JobBusinessArea
    {
        [Key, Column("JobBusinessAreaId", Order = 0)]
        public int JobBusinessAreaId { get; set; }

        public int CrtUsrnm { get; set; }
        public DateTime CrtTmstmp { get; set; }
        public int LcUsrnm { get; set; }
        public DateTime LcTmstmp { get; set; }

        public int ProjectId { get; set; }
        public int AreaTypeId { get; set; }
        public int SourceId { get; set; }

    }

Answer 1

似乎EstimateProcessMod和PriceListProcessMod有很多共同之处。我建议利用它并将两个实体存储在单个表ProcessMod中。通过创建ProcessMod抽象类并使用Table attribute注释它。具体类只定义差异。

[Table("ProcessMod")]
public abstract class ProcessMod
{
    [Key, Column("ModId", Order = 0)]
    public int ModId { get; set; }
    public int ProcessId { get; set; }
    public int Quantity { get; set; }
    public bool IsIncluded { get; set; }
    public int CrtUsrnm { get; set; }
    public DateTime CrtTmstmp { get; set; }
    public int LcUsrnm { get; set; }
    public DateTime LcTmstmp { get; set; }
    public decimal? CommisionPercentage { get; set; }
    public bool? IsProportionalyFixed { get; set; }
}

public class EstimateProcessMod : ProcessMod
{
    public int? SplitId { get; set; }
    [ForeignKey("ProcessId")]
    public virtual EstimateProcess EstimateProcess{ get; set; }
}

public class PriceListProcessMod : ProcessMod
{
    [ForeignKey("ProcessId")]
    public virtual PriceListProcess PriceListProcess { get; set; }
}

[Table("ProcessRelation")]
public class ProcessRelation
{
    [Key, Column("AreaId", Order = 0)]
    public int AreaId { get; set; }
    [Key, Column("ModId", Order = 1)]
    public int ModId { get; set; }
    [Key, Column("PriceSourceTypeId", Order = 2)]
    public int PriceSourceTypeId { get; set; }
    public int CrtUsrnm { get; set; }
    public DateTime CrtTmstmp { get; set; }
    public int LcUsrnm { get; set; }
    public DateTime LcTmstmp { get; set; }

    [ForeignKey("PriceSourceTypeId")]
    public virtual BillingProjectCode PriceSourceTypeCode { get; set; }
    [ForeignKey("AreaId")]
    public virtual JobBusinessArea JobBusinessArea { get; set; }

    [ForeignKey("ModId")]
    public virtual ProcessMod ProcessMod { get; set; }
}

您可能可以在ProcessRelation类中删除PriceSourceTypeId并将其移至ProcessMod类并使其成为鉴别器，或者您可能根本不需要使用它。这实际上取决于应用程序的其余部分。

您可能会对Table per Hierarchy感兴趣，了解其工作原理。

实体框架 - 条件关系 - 一个子表到一个或其他parrent表

1 个答案: