Entity Framework The relationship could not be changed because one or more of the foreign-key properties is non-nullable

Question

I have done the following configuration

public class ProductEligibiltyConfiguration : EntityTypeConfiguration<ProductEligibilty>
{
    public ProductEligibiltyConfiguration()
    {
        HasKey(t => t.Id).ToTable("ecom_ProductEligibilty");
        HasRequired(a => a.Product)
            .WithMany(t => t.MeetingProductEligibilty)
            .HasForeignKey(k => k.ProductId)
            .WillCascadeOnDelete(false);
        HasRequired(t => t.MemberType).WithMany().HasForeignKey(k => k.MemberTypeId).WillCascadeOnDelete(false);
    }
}

but getting the error while adding, deleting, updating the table.

Using following code to update while I have set all the references and objects for them as well.

foreach (var eligibleProduct in productEligibiltyes)
        {
          ProductEligibiltys.Attach(eligibleProduct);
          Entry(eligibleProduct).State = EntityState.Modified;
          ProductEligibiltys.Add(eligibleProduct);
       }

Getting error : The operation failed: The relationship could not be changed because one or more of the foreign-key properties is non-nullable. When a change is made to a relationship, the related foreign-key property is set to a null value. If the foreign-key does not support null values, a new relationship must be defined, the foreign-key property must be assigned another non-null value, or the unrelated object must be deleted.

Answer 1

I have noticed a bug in your code which might fix the issue. Actually you are doing Entry(eligibleProduct).State = EntityState.Modified; when adding new object object ProductEligibiltys.Add(eligibleProduct);

You should remove this line. Final code will look like this:

foreach (var eligibleProduct in productEligibiltyes)
   {
      ProductEligibiltys.Attach(eligibleProduct);
      ProductEligibiltys.Add(eligibleProduct);
   }