Foreign key created in shadow and appending random 1 to column name

Question

When I migrate my new models and data I get the following error for multiple foreign keys:

The foreign key property 'InsurancePolicy.InsuranceSubjectID1' was created in shadow state because a conflicting property with the simple name 'InsuranceSubjectID' exists in the entity type, but is either not mapped, is already used for another relationship, or is incompatible with the associated primary key type.

The weird thing is that I define my relationships the same throughout all models, but some work okay (FK without 1 is stored) and some don't.

Example of my models:

public class InsurancePolicy
{
    public int InsurancePolicyID { get; set; }
    [DataType(DataType.Currency)]
    [Column(TypeName = "money")]
    public decimal FinalSum { get; set; }
    public DateTime DateFrom { get; set; }
    public DateTime DateTo { get; set; }
    public int? InsuredID { get; set; }
    public Insured? Insured { get; set; }
    public int? InsuranceSubjectID;
    public InsuranceSubject? InsuranceSubject { get; set; }
    public int? InsuranceSubtypeID;
    public InsuranceSubtype? InsuranceSubtype { get; set; }
}

public class InsuranceSubject
{
    public int InsuranceSubjectID { get; set; }
    [Required]
    [StringLength(50)]
    public string Title { get; set; }
    public string Description { get; set; }
    [DataType(DataType.Currency)]
    [Column(TypeName = "money")]
    public decimal EstimatedValue { get; set; }
    public int? InsuredID;
    public Insured? Insured;
    public int? InsuranceSubjectTypeID { get; set; }
    public InsuranceSubjectType? InsuranceSubjectType { get; set; }
    public ICollection<InsurancePolicy>? InsurancePolicies { get; set; }
}

I tried my code without the foreign key properties and only left the reference navigation property (deleted the int and left the object) and it worked okay, but I need FK ints for future implementation.

Here is GitHub repo link for more insight (branch model-extension): https://github.com/lenartgolob/Insurance-IS/tree/model-extension

Answer 1

Ok.. For me.

I had Parent/Child relationship.

And I had put in properties (on the poco's) on (all the) scalar's (on the child) (where one of those scalars was the parent-FK (as int)), and had defined the ORM mapping (again, on the child) for this (same) scalar FK "int".

public class MyParent
{
    public int MyParentKey { get; set; }


    public ICollection<MyChild> MyKids { get; set; }

}


public class MyChild
{
    public int MyChildKey { get; set; }

    public int MyParentKey { get; set; } /* FK Scalar */

    public MyParent TheMyParent { get; set; }

}

(repeating myself) : I had Orm-Mapped the MyParentKey the SCALAR (in this case an "int") on the MyChildOrmMap.

But I had NOT orm-mapped the OBJECT (in this case the "MyParent" object).. via the property that pointed to that object (in this case the "TheMyParent" property).

Once I coded the 1:N relationship for the OBJECT (in this case the 'TheMyParent') (and the reciprocal MyKids), the error went away.

Aka, I was missing the below "HasOne/WithMany" orm-mapping (the below code would be in the MyChildMap (the fluent orm map)

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;

        builder.HasOne<MyParent>(me => me.TheMyParent)
            .WithMany(parent => parent.MyKids)
            .HasForeignKey(me => me.MyParentKey)
            .HasConstraintName("FK_MyChild_To_MyParent_MyParentKey");