hi I hope I understood what you are looking for.
First of al you should do a few changes to your model
public class Project
{
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public virtual ICollection<Survey> Surveys { get; set; }
}
public class Survey
{
public int Id { get; set; }
public int ProjectId { get; set; }
public int CategoryId { get; set; }
public string Name { get; set; }
public virtual Project Project { get; set; }
public virtual Category Category { get; set; }
public virtual ICollection<SurveyCategory> SurveyCategory { get; set; }
}
public class Category
{
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<Survey> Surveys { get; set; }
public virtual ICollection<SurveyCategory> SurveyCategory { get; set; }
}
public class SurveyCategory
{
public int Id { get; set; }
public string Name { get; set; }
public int SurveyId { get; set; }
public virtual Survey Survey { get; set; }
public int CategoryId { get; set; }
public virtual Category Category { get; set; }
}
And then on the model creating you should do this
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Project>()
.HasMany(p => p.Surveys)
.WithRequired(u => u.Project);
modelBuilder.Entity<Category>()
.HasMany(p => p.Surveys)
.WithRequired(u => u.Category);
modelBuilder.Entity<Category>()
.HasMany(p => p.SurveyCategory)
.WithRequired(u => u.Category)
.HasForeignKey(k => k.CategoryId)
.WillCascadeOnDelete(false);
modelBuilder.Entity<Survey>()
.HasMany(p => p.SurveyCategory)
.WithRequired(u => u.Survey)
.HasForeignKey(k => k.SurveyId)
.WillCascadeOnDelete(false);
}
I hope this helps