"EntityType has no key defined" exception although key is defined with HasKey

Question

Using EF 5 (reverse engineered code first), my model was working fine until it suddenly stopped.

\tSystem.Data.Entity.Edm.EdmEntityType: : EntityType 'ProjectsDate' has no key defined. Define the key for this EntityType.

\tSystem.Data.Entity.Edm.EdmEntityType: : EntityType 'ProjectsRisk' has no key defined. Define the key for this EntityType.

I define a key using fluent API rather than attributes, here is my ProjectsDates classes.

public partial class ProjectsDate
{
    public string OSProjectCode { get; set; }
    public Nullable<System.DateTime> TargetStart { get; set; }
    public Nullable<System.DateTime> EndDateOriginal { get; set; }
    public Nullable<System.DateTime> EndDateChangeControl { get; set; }
    public Nullable<System.DateTime> EndDateActual { get; set; }
    public Nullable<System.DateTime> GoLiveAgreed { get; set; }
    public Nullable<System.DateTime> GoLiveActual { get; set; }
    public virtual Project Project { get; set; }
}

public class ProjectsDateMap : EntityTypeConfiguration<ProjectsDate>
{
    public ProjectsDateMap()
    {
        // Primary Key
        this.HasKey(t => t.OSProjectCode);

        // Properties
        this.Property(t => t.OSProjectCode)
            .IsRequired()
            .HasMaxLength(10);

        // Table & Column Mappings
        this.ToTable("ProjectsDates");
        this.Property(t => t.OSProjectCode).HasColumnName("OSProjectCode");
        this.Property(t => t.TargetStart).HasColumnName("TargetStart");
        this.Property(t => t.EndDateOriginal).HasColumnName("EndDateOriginal");
        this.Property(t => t.EndDateChangeControl).HasColumnName("EndDateChangeControl");
        this.Property(t => t.EndDateActual).HasColumnName("EndDateActual");
        this.Property(t => t.GoLiveAgreed).HasColumnName("GoLiveAgreed");
        this.Property(t => t.GoLiveActual).HasColumnName("GoLiveActual");

        // Relationships
        this.HasRequired(t => t.Project)
            .WithOptional(t => t.ProjectsDate);

    }
}

Why doesn't EF see my fluent API mapping?

Maybe you didn't add an instance of `ProjectsDateMap` to `modelBuilder.Configurations` in `OnModelCreating`? — Slauma, May 09 '13 at 12:43
Just double checked, it is in OnModelCreating, cheers anyway — Malkin, May 09 '13 at 12:47
What a pity, it had been such a simple explanation and fix :) Did you check in the debugger if the `HasKey` line is actually passed? — Slauma, May 09 '13 at 12:50
Aye, I was ready to be embarrassed but happy it was working aha ;p. If I breakpoint the modelmap class should it be hit? I can't seem to hit the `OnModelCreating` or `HasKey` — Malkin, May 09 '13 at 12:56
Yes, it should hit the line when you use a context for the first time after application start. Is this a project converted from db-first or model-first? Is it possible that you have an edmx somewhere still in the project or a connection string that contains metadata sections? EF would not see it as Code-First then and never call `OnModelCreating`. — Slauma, May 09 '13 at 13:00
Hmm, I used EF Power Tools to reverse engineer from a database. — Malkin, May 09 '13 at 13:07
Also, to throw a curve ball in, I recreated another context I also have, and this has made this context work and hit the breakpoints. Would this mean EF failed silently loading the first context and didn't bother getting to the second? — Malkin, May 09 '13 at 13:08
Hm, don't understand exactly. Do you mean that in a second `using (var ctx = new MyContext())` `OnModelCreating` is called but not on the first one? You can btw edit your question to put new infos in there (use "edit" link below your question). It's a better place then a long comment thread. (I've changed your question title btw. "Entity Framework" wasn't that good as a meaningful title :)) — Slauma, May 09 '13 at 13:12

score 2 · Accepted Answer · answered Sep 19 '13 at 05:48

2

For some reason (probably a bug), FluentAPI needs the key to be defined in a convention way - that is - ClassName + Id, or in your case:

ProjectsDateId

This way the metadata created by EF can acknowledge the fact it is related. Very annoying but...

answered Sep 19 '13 at 05:48

Tomer

4,382
5
38
48

Does not work. I have an entity named Offer, and I set the key to be named OfferID, but EF still complains no key is defined. The only thing that works is using [Key,ForeignKey("Offer")] on the property, and then the property can be named anything I want. – Triynko Feb 27 '18 at 16:14

score 1 · Answer 2 · edited Dec 08 '16 at 04:18

You need to have a global binding or individual binding in OnModelCreating
(DbModelBuilder modelBuilder).

So it would look something like this in your context file:

public override void OnModelCreating(DbModelBuilder modelBuilder)
{
    // global
    modelBuilder.Configurations.AddFromAssembly(GetType().Assembly);
    // individual
    modelBuilder.Configurations.Add(new ProjectsDateMap());
}

score 0 · Answer 3 · answered Jul 09 '13 at 08:22

I fixed this by re-running the reverse engineer code first from EF power tools. Seemed to work from there out, this seems to be a general problem that kicks up when your models aren't configured right. It's a shame it seems so general and just kicks up misleading errors.

"EntityType has no key defined" exception although key is defined with HasKey

3 Answers3

Linked