实体框架基本属性映射

Question

Hello I have a problem with my mapping.

I have classes in hierarchical structure:

1. TaxYear
2. Owner
3. EconomyUnit
4. Report
5. ReportItem
6. Invoice

All this classes have a base class "BaseEntity" and a parent property and parent_id property.

The invoice parent property is not from type "ReportItem" because "Onwer" has a seperate invoice list so the type is "BaseEntity".

This works fine I can use as parent "ReportItem" and "Owner".

But now I want to "move" the invoices between parents. At this moment only from "ReportItem" to "ReportItem".

Set the new parent:

foreach (var invoice in oldReportItem.Invoices)
{
    invoice.Parent = newReportItem;
}
ctx.SaveChanges();

This works without errors but not correctly. EF created three columns for my parent property.

• Owner_Id
• ReportItem_Id
• Parent_Id

If you insert a invoice then both columns will get the same Id. Works fine but if you set a new parent then "Onwer_Id" or ReportItem_Id will be set to null and Parent_Id will only be updated.

There is my problem. I think my mapping is wrong. Can anyone help me?

Fluent-Api

modelBuilder.Entity<ReportItem>()
    .HasOptional(p => p.Parent)
    .WithMany(p => p.Items)
    .HasForeignKey(k => k.ParentId)
    .WillCascadeOnDelete(false);

BaseEntity:

public abstract class BaseEntity
{
    [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public Guid Id { get; set; }

    public abstract String GetName();

    public DateTime? CreateDate { get; set; }
    public DateTime? LastEditDate { get; set; }

    public BaseEntity DeepCopy()
    {
        return (BaseEntity)MemberwiseClone();
    }
}

Owner:

public class Owner : BaseEntity
{
    public Owner()
    {
        Items = new ObservableCollection<EconomyUnit>();
        PrivateInvoices = new ObservableCollection<Invoice>();
    }

    [Required]
    public String Name { get; set; }

    [Required]
    public TaxYear Year { get; set; }
    public Guid? YearId { get; set; }

    public ICollection<EconomyUnit> Items { get; private set; }
    public ICollection<Invoice> PrivateInvoices { get; private set; }

    public override string GetName()
    {
        return Name;
    }
}

ReportItem:

public class ReportItem : BaseEntity
{
    public ReportItem()
    {
        Items = new ObservableCollection<Invoice>();
    }

    [Required]
    public String Name { get; set; }

    public ICollection<Invoice> Items { get; private set; }

    public Guid? ParentId { get; set; }
    public Report Parent { get; set; }
}

Invoice:

public class Invoice: BaseEntity
{
    public String Name { get; set; }

    public Guid? ParentId { get; set; }

    public BaseEntity Parent { get; set; }

}

Thank you Lyror

Answer 1

Ok, let's start with the OP.

I have classes in hierarchical structure:

TaxYear Owner EconomyUnit Report ReportItem Invoice

Your class structures indicate that TaxYear is optional so it cannot be a parent (by definition). Some of your classes are missing so I cannot determine if any other relationships are flawed. Taking your statement at face value, your classes would be more like this (extraneous fields removed for clarity)

public abstract class BaseEntity - Unchanged

public class Owner : BaseEntity
{
    // Parent navigation    
    public Guid YearId { get; set; }
    public virtual TaxYear Year { get; set; }

    // Child navigation
    public virtual ICollection<EconomyUnit> Units { get; private set; }
}

public class EconomicUnit : BaseEntity
{
    // Parent navigation    
    public Guid OwnerId { get; set; }
    public virtual Owner Owner { get; set; }

    // Child navigation
    public virtual ICollection<Report> Reports { get; private set; }
}

public class Report : BaseEntity
{
    // Parent navigation    
    public Guid UnitId { get; set; }
    public virtual EconomicUnit Unit { get; set; }

    // Child navigation    
    public virtual ICollection<ReportItem> Items { get; private set; }
}

public class ReportItem : BaseEntity
{
    // Parent navigation    
    public Guid ReportId { get; set; }
    public virtual Report Report { get; set; }

    // Child navigation    
    public virtual ICollection<Invoice> Invoices { get; private set; }
}

public class Invoice : BaseEntity
{
    // Parent navigation    
    public Guid ReportItemId { get; set; }
    public virtual ReportItem ReportItem { get; set; }
}

If you want to see a list of Invoices for an Owner, try this on:

dbContext.Invoices.Where(a => a.ReportItem.Report.EconomicUnit.Owner.Id == <parameter>).Include(b => b.ReportItem.Report.EconomicUnit.Owner.TaxYear).ToList();

Of course, you can select into a new DTO object inverting the relationship Owner ==> Invoices.