Mapping Odd relationship in Entity Framework 6 - entity-framework

Question

I have a set of 3 models, which is an odd many-to-many-ish relationship.
public class Metric {
public int Id { get; set; }
public string Name { get; set; }
// ...
}
public class ActionPlan {
public int Id { get; set; }
public string Name { get; set; }
public DateTime StartDate { get; set; }
//...
public virtual ICollection<Metric> Metrics { get; set; }
}
public class PlanMetric {
public int PlanId { get; set; }
public int MetricId { get; set; }
public decimal GoalValue { get; set; }
public virtual ActionPlan Plan { get; set; }
public virtual Metric Metric { get; set; }
}
I have the relationships mapped as follows:
public class PlanMetricMapping : EntityTypeConfiguration<PlanMetric> {
public PlanMetricMapping() {
ToTable("PlanMetric");
HasKey(m => new {
m.MetricId,
m.PlanId
});
Property(m => m.GoalValue)
.IsRequired()
.HasPrecision(10, 2);
HasRequired(m => m.Metric)
.WithMany()
.HasForeignKey(m => m.MetricId);
HasRequired(m => m.Plan)
.WithMany()
.HasForeignKey(m => m.PlanId);
}
}
public class ActionPlanMapping : EntityTypeConfiguration<ActionPlan> {
public ActionPlanMapping() {
ToTable("ActionPlan");
HasKey(m => m.Id);
// ...
//HasMany(m=>m.Metrics) // how do I get to this data?
}
}
The problem is
1) EF is creating an ActionPlan_Id field in my Metric table, and I'm not sure why.
2) I don't know how to set up my mapping to be able to navigation from a Plan to it's Metrics.

Answer 1

EF is creating an ActionPlan_Id field because you have
public virtual ICollection<Metric> Metrics { get; set; }
in your ActionPlan definition, which EF interprets as a one-to-many relationship between ActionPlan and Metric. It seems like you want
public virtual ICollection<PlanMetric> PlanMetrics { get; set; }
instead.
Then, in order to get to an ActionPlan's metrics, you could go through that collection, perhaps through a Select().