Representing Complex objects in Entity Framework Core

Question

For example, lets say I had this object that I wanted to put into a SQL database with EntityFramework:

public class Shift
{
    public Guid Id { get; set; }

    public Attendance Attendance { get; set; }
    public Managers Managers { get; set; }

    // other properties
}

public class Attendance
{
    public int AM { get; set; }
    public int MidDay { get; set; }
    public int PM { get; set; }
}

public class Managers
{
    public string AM { get; set; }
    public string MidDay { get; set; }
    public string PM { get; set; }
}

Normally, I would figure this cannot be done, and I would just flatten everything into a simple collection of properties:

public class Shift
{
    public Guid Id { get; set; }

    public int Attendance_AM { get; set; }
    public int Attendance_MidDay { get; set; }
    public int Attendance_PM { get; set; }

    public string Managers_AM { get; set; }
    public string Managers_MidDay { get; set; }
    public string Managers_PM { get; set; }
}

But is there a way to make EF store the complex object as a single table?

EDIT

This might help illustrate my question.

The goal is to have both code blocks above, work with the same Table in SQL:

Why do you care that it's stored as a single table? That is to say... If you're using an ORM, it's so that you can stop worrying about the implementation detail. The classes you've defined could easily fit in a multi-table model. — Basic
– Basic, Commented Mar 3, 2017 at 20:23
A few reasons: 1) Its something that I've thought about a few times in EF, but never found a good answer. 2) It seems ridiculous to me to create a whole table just to store one or two points of data, and then have to have SQL join them when I need them. 3) Logically, all this data should be in the same table, as it constitutes one single entity. 4) (the big one) I'm working with an existing DB schema. — Adam Schiavone
– Adam Schiavone, Commented Mar 3, 2017 at 20:28
Not sure I follow. Do you have a separate table in your existing DB schema? It would be better if you show the tables and ask how to map them in EF then. — Ivan Stoev
– Ivan Stoev, Commented Mar 3, 2017 at 20:30
I'll make a table and edit with a screenshot to help illustrate. — Adam Schiavone
– Adam Schiavone, Commented Mar 3, 2017 at 20:33
But if you ask for so called Complex Types, they are not supported yet in EF Core, but were in EF6 and will be in Core later. — Ivan Stoev
– Ivan Stoev, Commented Mar 3, 2017 at 20:35

glennsl · Accepted Answer · 2017-09-30 18:18:05Z

3

Add the following in the OnModelCreating() of your context class. It works with .NET Core 2.0 only:

 modelBuilder.Entity<Shift>().OwnsOne(s => 
             { cb.OwnsOne(c => c.Attendance);
               cb.OwnsOne(c => c.Managers);
             });

edited Sep 30, 2017 at 18:18

glennsl

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answered Sep 30, 2017 at 16:28

Bashir M. Saad

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1 Comment

TheHvidsten Over a year ago

What is cb? This variable is not defined in your answer or in the original question.

MartinF · Accepted Answer · 2017-06-06 11:47:58Z

1

This feature will be available in Entity Framework Core 2. Currently Entity Framework Core 2 is in Preview, but the feature is not complete in Preview 1, but can instead be used by using their nightly builds.

You can read about it here: https://blogs.msdn.microsoft.com/dotnet/2017/05/12/announcing-ef-core-2-0-preview-1/

(The feature is already available for "regular" Entity Framework)

answered Jun 6, 2017 at 11:47

MartinF

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Comments

AhuraMazda · Accepted Answer · 2023-05-22 21:41:58Z

0

I am very supprised to face this kind of problem in .net world. Java Hibernate provides very easy solution for this.

So thanks to comments and Bashir M. Saad answer I find a solution.

You should add [Owned] annotation at the top of nested object without adding primary key. For more information please visit. https://learn.microsoft.com/en-us/ef/core/modeling/owned-entities

answered May 22, 2023 at 21:41

AhuraMazda

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