Entity Framework Multiple Many to Many Relationships using Code First

Question

I have 2 classes Foo and Bar

public class Foo
    {
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public virtual int Id { get; set; }


        private ICollection<Bar> _bar;
        public virtual ICollection<Bar> Bars
        {
            get { return _bar?? (_bar= new Collection<Bar>()); }
            set { _bar= value; }
        }
    }

Bar

 public class Bar
        {
            [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
            public virtual int Id { get; set; }


            private ICollection<Foo> _foo1;
            public virtual ICollection<Foo> Foos1
            {
                get { return _foo1?? (_foo1= new Collection<Foo>()); }
                set { _foo1= value; }
            }

               private ICollection<Foo> _foo2;
                public virtual ICollection<Foo> Foos2
                {
                    get { return _foo2?? (_foo2= new Collection<Foo>()); }
                    set { _foo2= value; }
                }


            }

I then use Migration to update the database. However, instead of having an usual table FooBar. EF creates 2 tables

Foo
Id,Bar_Id

Bar
Id,Foo_Id,Foo_Id1

which is not what I want. I guess I'm messing up by adding 2 collections of Foo into Bar. What should I do now?

Well, why do you have 2 collections? What are you trying to achieve? — Ales Ruzicka
– Ales Ruzicka, Commented Apr 23, 2015 at 10:13
Because that's the business rules that I have to apply. Think an item with 2 kind of taxes, so you will have bought taxes (taxes applied when you bought the item) and sold taxes (taxes will be applied when you sell the item). Now that you ask, maybe my model is not that good, any suggestion? — Quannt
– Quannt, Commented Apr 23, 2015 at 10:17

Quannt · Accepted Answer · 2015-04-23 10:47:07Z

Figured it out, I need to do 2 things to fix this. First, add another collection of Bar to Foo

 public class Foo
        {
            [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
            public virtual int Id { get; set; }


            private ICollection<Bar> _bar;
            public virtual ICollection<Bar> Bars
            {
                get { return _bar?? (_bar= new Collection<Bar>()); }
                set { _bar= value; }
            }

            private ICollection<Bar> _bar2;
            public virtual ICollection<Bar> Bars2
            {
                get { return _bar2?? (_bar2= new Collection<Bar>()); }
                set { _bar2= value; }
            }
        }

Second, use InverseProperty to explicitly tell EF that I want 2 many-to-many relationships.

 public class Bar
        {
            [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
            public virtual int Id { get; set; }


            private ICollection<Foo> _foo1;
            [InverseProperty("Bars")]
            public virtual ICollection<Foo> Foos1
            {
                get { return _foo1?? (_foo1= new Collection<Foo>()); }
                set { _foo1= value; }
            }

               private ICollection<Foo> _foo2;
                [InverseProperty("Bars2")]
                public virtual ICollection<Foo> Foos2
                {
                    get { return _foo2?? (_foo2= new Collection<Foo>()); }
                    set { _foo2= value; }
                }


            }

I now end up with 4 table Foo,Bar,FooBarss and FooBar1

Collectives™ on Stack Overflow

Entity Framework Multiple Many to Many Relationships using Code First

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related