Howto map value object in Entity Framework Core 2.0

Question

Consider a Customer entity that has a Resource object representing the logo of the customer:

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

    public string CompanyName { get; set; }

    public Resource Logo { get; set; }
}

public class Resource
{
    public string Uri { get; set; }

    public string Name { get; set; }
}

This is what I have tried so far but getting an error because Logo is a complex object:

var customer = modelBuilder.Entity<Customer>().ToTable("Customers");
customer.HasKey(c => c.Id);
customer.Property(c => c.CompanyName).HasColumnName("Company");
customer.Property(c => c.Logo);

How can I store that Resource with EF Core 2.0 as a value object inside the customer table?

Federico Dipuma · Accepted Answer · 2017-09-02 15:38:59Z

15

If you want to share the same table you could simply define an Owned Entity:

modelBuilder.Entity<Customer>().OwnsOne(c => c.Logo);

By convention it will use just one table.

answered Sep 2, 2017 at 15:38

Federico Dipuma

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3 Comments

Martin Brandl Over a year ago

That's what I was looking for! Thank you! (can accept answer in 4 min)

FercoCQ Over a year ago

If I need to define the column names of the complex type properties with fluent API, do I do it just as if it was a normal entity? something like modelBuilder.Entity<Resource>().Property(r => r.Name).HasColumnName("ResourceName");

Federico Dipuma Over a year ago

@FercoCQ You need to define those properties inside OwnsOne method: modelBuilder.Entity<Customer>().OwnsOne(c => c.Logo, x => { x.Property(p => p.Logo).HasColumnName("LogoColName"); });

Italo José · Accepted Answer · 2017-09-19 00:36:52Z

1

Read More About it here there have a exemple
Search with CTRL + F by "Owned entities and Table Splitting"

answered Sep 19, 2017 at 0:36

Italo José

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1 Comment

Álvaro García Over a year ago

It is a good starting point, thanks for share, but it doesn't tell so much, for example, how to define the name of the columns in the database, if you don't want the default behavior that you get using only OwnsOne(). Perhaps you could be interested in this documentation: learn.microsoft.com/en-us/ef/core/modeling/owned-entities

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