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POmake both models aware of each other with a one-to-one relationship in asp.net entity framework
 

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  1. POmake both models aware of each other with a one-to-one relationship in asp.net entity framework
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    <p>I am unable to get the one to one relationship with EF to work properly. I've scored blogs, SO, and msdn docs, but nothing I do seems to work. </p> <p>I have two models, a Class and an Exam that look like the following:</p> <pre><code>[Table("classes")] public class Class { [Key] [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)] public int Id { get; set; } [StringLength(255), Required] public string Title { get; set; } public virtual Exam Exam { get; set; } } [Table("exams")] public class Exam { [Key] [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)] public int Id { get; set; } [DisplayFormat(DataFormatString = "{0:h:mm tt}")] public DateTime? Time { get; set; } public int ClassId { get; set; } public virtual Class Class { get; set; } } </code></pre> <p>I want to be able to access the exam from the Class and the Class from the Exam, but no matter what I do, I find some error.</p> <p>Trying to create/run migrations I get the following.</p> <pre><code>The principal end of this association must be explicitly configured using either the relationship fluent API or data annotations. </code></pre> <p>If I add this to my context:</p> <pre><code>protected override void OnModelCreating(DbModelBuilder builder) { builder.Entity&lt;Exam&gt;() .HasRequired(e =&gt; e.Class) .WithOptional(c =&gt; c.Exam); } </code></pre> <p>I get the following error:</p> <pre><code>System.Data.Entity.Infrastructure.DbUpdateException: Entities in 'BenchContext.Exams' participate in the 'Class_Exam' relationship. 0 related 'Class_Exam_Source' were found. 1 'Class_Exam_Source' is expected. ---&gt; System.Data.UpdateException: Entities in 'BenchContext.Exams' participate in the 'Class_Exam' relationship. 0 related 'Class_Exam_Source' were found. 1 'Class_Exam_Source' is expected. </code></pre> <p>I'm not sure how to tell the fluent api how to correctly foreign key between the two models and nothing I do seems to affect it.</p> <p>What am I missing?</p>
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