Entity Framework entity splitting one to many

Question

We are trying to use EF as a Business Entity Mapping model. Instead of generating 1 table per class we would like to flatten out the tables (entity splitting) and generate a business object for the class, letting Entity Framework handle the CRUD.

In addition we have an existing database and cannot modify the schema. We have tried both code-first and database first solutions, but we are unable to get to our stated goal.

What we have:

 public class Call
 {
    public int CallId {get;set;}
    public DateTime callTime {get;set;}
    public int PhoneTypeId {get; set;}

    public virtual PhoneType PhoneType {get; set;}
}

public class PhoneType 
{
     public int PhoneTypeId {get ;set;}
     public string TypeOfPhone {get ;set;}
}

What we want:

public class CallDetails
{    
    public int CallId {get;set;}
    public DateTime callTime {get;set;}
    public string TypeOfPhone {get; set;}
}

Edit

We are on ef 5 but can go up to ef 6.

Edit

To state the question clearer, I am looking for a way to flatten out multiple tables into 1 single entity, then have EF automagically update the multiple tables when that one edit is saved back to the data context

Edit

Is there a way of mapping 1 entity to second, if the first entity has the primary key of the second and the second entity doesnt have any key relating back to the first?

Can you give more details about how entity splitting didn't work? This article appears to describe how to do exactly what you're asking: https://msdn.microsoft.com/en-us/data/jj715646.aspx — Dave, Feb 16 '16 at 21:12
You title says *entity splitting one to many*, which is a contradictio in terminis. But the example is 1:1. So what do you mean? Maybe showing the database schema could shed some light on this. — Gert Arnold, Feb 16 '16 at 21:18
@GertArnold The example is 1 - Many if you look at it from the phonetype. There is 1 phonetype with many phones — gh9, Feb 16 '16 at 21:19
You basically look for a way to have children copy some values from their parents. EF doesn't provide any mapping strategy for that. — Gert Arnold, Feb 16 '16 at 21:23
@GertArnold The only thing that comes close to what I want, is that both entites Must share the same key. Can we create a mapping where 1 entity has the key of the second, but the second entity doesnt have the key of the first? — gh9, Feb 16 '16 at 21:28
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/103649/discussion-between-gh9-and-gert-arnold). — gh9, Feb 16 '16 at 21:31

score 2 · Accepted Answer · answered Feb 16 '16 at 21:55

If you don't like how EF builds the class for you, create your own just as you want it. (I wrote the following assuming you have C# 6)

public class CallDetails
{
    public Call entityCall { get; set;}
    public int CallId => entityCall.CallId;
    public DateTime callTime {
            get{ return entityCall.callTime;}
            set{ entityCall.callTime = value;}
        }
    public string TypeOfPhone => entityCall.PhoneType.TypeOfPhone;
}

Then when you use it

var details = new CallDetails(){ entityCall = db.Calls.Find(id) };

You can access the values in the structure that you set up.That being said, I'd suggest using EF's classes. Doing it this way can cause a headache when it comes to editing values in the database.

Entity Framework entity splitting one to many

1 Answers1