CODEWITHSUNDEEP
c#entity-framework
Ben Rubin
Ben Rubin

Reputation: 7341

Errors with non-mapped child entity

I have a Parent and Child class/table and I'm using Fluent API to configure my mapping. The tables are joined on non primary key fields in each table, so according to what I've read, I can't configure the join in Entity Framework. Because of that, I'm going to load my Parent.Children property manually (parent.Children = (from x in context.Children...)

However, I'm getting an exception on my mapping of Parent. My classes look like

public class Parent
{
   // Unique primary key
   public int ParentPrimaryKey { get; set; }

   // These two fields together compose the foreign key to join to Child
   public string ParentForeignKey1 { get; set; }
   public string ParentForeignKey2 { get; set; }

   public List<Child> Children { get; set; }
}

public class Child
{
   // Unique primary key
   public int ChildPrimaryKey { get; set; }

   // These two fields together compose the (non-unique) foreign key to join to Parent
   public string ChildForeignKey1 { get; set; }
   public string ChildForeignKey2 { get; set; }

}

When I try to query context.Parents, I get an exception because the SQL that Entity Framework generates is trying to join Parent to Child and is looking for a property on Child called Child_ParentPrimaryKey.

If I add modelBuilder.Entity<Parent>().Ignore(p => p.Children); I get the exception System.NotSupportedException: The specified type member 'Packages' is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported.

How can I keep Children as a non-mapped property on Parent without getting errors?

Upvotes: 0

Views: 172

Answers (2)

Ben Rubin
Ben Rubin

Reputation: 7341

Thanks to everyone who responded. Your comments made me realize the problem was that I was using the Parent.Children property in my LINQ query. I removed that, and it's working now.

Upvotes: 0

Georg Patscheider
Georg Patscheider

Reputation: 9463

You can exclude a property from EF mapping by adding the [NotMapped] attribute:

using System.ComponentModel.DataAnnotations.Schema;
public class Parent {
   // ...

   [NotMapped]
   public List<Child> Children { get; set; }
}

DataAnnotations - NotMapped Attribute

Upvotes: 1

Related Questions