Entity Framework Code First Case Sensitivity on string PK/FK Relationships

Question

I have a fairly simple composite one to many relationship defined using POCO/Fluent API, one column of which is a string.

I\'ve discovered that the data in this col

Answer 1

EF Insensitive join comparison

Hi I'm having the same problem (although not wit code first, but with a generated model)

The cause is that EF makes a case-sensitive comparison of the key fields, and it doesn'n find the related objects.

I'm guessing the problem lies in the "EDM Relationship Manager" and maybe there's a possibility of overriding this behavior.

I found a simple workaround for this: lower casing the related properties:

    [EdmScalarPropertyAttribute(EntityKeyProperty=true, IsNullable=false)]
    [DataMemberAttribute()]
    public global::System.String id
    {
        get
        {
            return _id.ToLower(); // **<- here**
        }
        set
        {
            if (_id != value)
            {
                OnidChanging(value);
                ReportPropertyChanging("id");
                _id = StructuralObject.SetValidValue(value, false);
                ReportPropertyChanged("id");
                OnidChanged();
            }
        }
    }
    private global::System.String _id;
    partial void OnidChanging(global::System.String value);
    partial void OnidChanged();

It actually works, but, of course, it's a lame workoround. I'm sticking to it for a while util I (or somebody) comes out with a better solution.

Good Luck!

Answer 2

I came up with a workaround that manually "stitches up" the association after the context has retrieved the appropriate rows from the database. Translated to your problem it would be along these lines:

//Your original query
var members = context.Member.Include(m => m.Audits).First(m => m.Id == id); 

//The "stitch up" code that should probably be moved to a method of the data context.
var membersWithoutAudits = context.Members.Local.Where(m => !m.Audits.Any()).ToList();
foreach (var nextMember in membersWithoutAudits) {
  //Now we can populate the association using whatever logic we like
  nextMember.Audits = context.Audits.Local.Where(a => a.MemberId.ToLower() == nextMember.Id.ToLower()).ToList();
}

Notice how we use the context.[DbSet].Local property to ensure that we do all the "stitch up" in memory without making any further SQL calls. I also fetch the members without audits as a performance optimization so we are not re-doing the work of EF's association (in the cases where it did work). But you could just as easily remap every "member" instance.