Code First Foreign Key Configuration in Many to Many Relationships

Question

I have created two table.
Table 1: Parent table with ParentId and ParentName fields.In this ParentId is primary key.
Table 2: Child table with ChildId and ChildName fields.In this ChildId is primary key.
I want to get the ParentId and ChildId into another table.So icreated table in the name MappingParentChild with ParentId1,ChildId1.I want this ParentId1 and ChildId1 as foreign key. How can i achive this.

public class Parent
{
public int ParentId { get; set; } //Primary key
public string ParentName { get; set; }
}
public class Child
{
public int ChildId { get; set; } //Primary key
public string ChildName { get; set; }
}
public class MappingParentChild
{
public int Id { get; set; }
public int ParentId1 { get; set; } // want Foreign key for Parent(ParentId)
public int ChildId1 { get; set; }// want Foreign key for Child(ChildId)
}
public class MappingParentChildConfiguration :EntityTypeConfiguration<MappingParentChild>
{
public MappingParentChildConfiguration()
{
ToTable("MappingParentChild");
Property(m => m.Id).IsRequired();
Property(m => m.ParentId1).IsRequired();
Property(m => m.ChildId1).IsRequired();
}
}

How can i do this.Please help me.

Are you using Entity Framework. If so, which version? I assume it's EF from your title. — Peter Smith
Any specific reason why you are creating the MappingParentChild class? Because EF does not need it to create many-to-many relations — SOfanatic

user2285613 user2285613 · Accepted Answer · 2013-08-16T10:13:48

public class Parent
{
public int ParentId { get; set; }
public string ParentName { get; set; }
public virtual ICollection<MappingParentChild> parent{ get; set; }
}

public class Child
{
public int ChildId { get; set; }
public string ChildName { get; set; }
public virtual ICollection<MappingParentChild> child { get; set; }
}

public class MappingParentChild
{
public int Id { get; set; }
public int ParentId1 { get; set; }
public int ChildId1 { get; set; }
public virtual Parent pt{ get; set; }
public virtual Child Ch{ get; set; }
}

public class MappingParentChildConfiguration : EntityTypeConfiguration<MappingParentChild>
{
public MappingParentChildConfiguration()
{
ToTable("MappingParentChild");
Property(m => m.Id).IsRequired();
HasRequired(m => m.pt).WithMany(e => e.parent).HasForeignKey(m => m.ParentId );
HasRequired(m => m.ch).WithMany(e => e.child ).HasForeignKey(m => m.ChildId );
}
}

Code First Foreign Key Configuration in Many to Many Relationships

1 Answers