實體框架一對零與不同的表

Question

我想知道是否有可能使許多表相關。

這是我現在（工作一到零或一關係之間ReportReportHeader）：我要添加表命名Style到Report也給

public class Report 
{ 
    public int Id {get; set;} 
    public ReportHeader ReportHeader {get; set;} 

    [ForeignKey("ReportHeader")] 
    public int ReportHeaderId {get; set;} 
} 

public class ReportHeader 
{ 
    [Key, ForeignKey("Report")] 
    public int Id {get; set;} 

    public Report Report {get; set;} 
} 

此時表ReportHeader。因此，關係是這樣的：

Report 
|--ReportHeader 
| |-- Style 
| 
|-- Style 

之後的類應該是這樣的：

public class Report 
{ 
    public int Id {get; set;} 

    public ReportHeader ReportHeader {get; set;} 
    public Style Style {get; set;} 

    [ForeignKey("ReportHeader")] 
    public int ReportHeaderId {get; set;} 

    [ForeignKey("Style")] 
    public int StyleId {get; set;} 
} 

public class ReportHeader 
{ 
    [Key, ForeignKey("Report")] 
    public int Id {get; set;} 

    [ForeignKey("Style")] 
    public int StyleId {get; set;} 

    public Report Report {get; set;} 
    public Style Style {get; set;} 
} 

這是這麼多的樂趣......直到它想想Style類。在這一點上，我不知道如何設計它。這甚至有可能使這個班級與不同的表格有兩種關係嗎？

public class Style 
{ 
    // ??? 
    //[Key, ForeignKey("Report"), ForeignKey("ReportHeader")] 
    public int Id {get; set;} 

    public ReportHeader ReportHeader {get; set;} 
    public Report Report {get; set;} 
} 

Answer 1

在這種情況下，你應該到面具你想要的關係：一到一個多到一：

public BaseClass 
{ 
    //indeed, collection always will have zero or one items 
    public virtual ICollection<Style> styles {get; set;} 

    [NotMapped] 
    public Style style { 
     get { return styles.FirstOrDefault(); } 
     set { styles.Add(value); }; 
    } 
} 

public class Report : BaseClass 
{ 
    //other stuff... 
} 

public class ReportHeader : BaseClass 
{ 
    //other stuff... 
} 

public class Style 
{ 
    public int Id {get; set;} 

    public virtual Report report {get; set;} 
    [Index(IsUnique = true)]//to ensure that relation is exactly one-to-one 
    public int? reportId {get; set;} 

    public virtual ReportHeader reportHeader {get; set;} 
    [Index(IsUnique = true)]//to ensure that relation is exactly one-to-one 
    public int? reportHeaderId {get; set;} 
}