Reputation: 1232
I am planning a simple two table structure:
1) Teacher Table :
public class TeacherAccount
{
[DataType(DataType.Text), Required()]
public string Name { get; set; }
[DataType(DataType.Text), Required()]
public string Address { get; set; }
[DataType(DataType.EmailAddress), Required(), Key]
public string Email { get; set; }
[DataType(DataType.Password), Required()]
public string Password { get; set; }
[DataType(DataType.Password), Compare("Password"), Required(), NotMapped]
public string ConfirmPassword { get; set; }
public bool Activated { get; set; }
}
2) Subjects taught by a teacher :
public class Teacher_Subject_Map
{
[ForeignKey("TeacherAccount")]
public string Email { get; set; }
public string Subjects;
}
My Concept is : For email identifying a teacher, there can be multiple subjects, which is taught by that teacher.
How ever I am getting this :
The ForeignKeyAttribute on property 'Email' on type 'xpertsdesk.Models.Teacher_Subject_Map' is not valid. The navigation property 'TeacherAccount' was not found on the dependent type 'xpertsdesk.Models.Teacher_Subject_Map'. The Name value should be a valid navigation property name.
as error in mvc5.
What I am trying to do :
Create table Teacher(Email varchar(30) Primary Key, Other Details);
Create table Subjects(Email varchar(30) References Teacher(Email), Subject varchar(30));
What am I doing wrong ?
Upvotes: 1
Views: 1392
Reputation: 3256
If a subject can be taught by only one teacher (one-to-many relationship):
In this case there will not be a mapping table.
public class Subject
{
[Key]
public string Name { get; set; }
// This will hold the Key of Teacher
public string TeacherEmail { get; set; }
[ForeignKey("TeacherEmail")]
public virtual Teacher Teacher { get; set; }
}
public class Teacher
{
/* the original properties comes here, e.g. Email */
public string Email { get; set; }
// Navigation property for taught subjects
public virtual ICollection<Subject> Subjects { get; set; }
}
If a subject can be taught by more teachers (many-to-many relationship):
The Subject
class would be like this.
public class Subject
{
[Key]
public string Name { get; set; }
/* other properties if needed */
public virtual ICollection<Teacher> Teachers { get; set; }
}
And then you can configure the many-to-many relationship in your own DbContext class:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder
.Entity<Teacher>()
.HasMany(teacher => teacher.Subjects)
.WithMany(subject => subject.Teachers)
.Map(c =>
{
c.ToTable("Teacher_Subject_Map");
c.MapLeftKey("TeacherEmail");
c.MapRightKey("SubjectName");
});
}
Upvotes: 2