Support inheritance for owned/property bag/shared-type entity types

For example, this from #9536:

public class Friend
{
    public int Id { get; set; }
    public string Name { get; set; }

    public FullAddress Address { get; set; }
}

public class LessThanFriend
{
    public int Id { get; set; }
    public string Name { get; set; }

    public CityAddress Address { get; set; }
}

public class CityAddress
{
    public string Cap { get; set; }
    public string City { get; set; }
}

public class FullAddress : CityAddress
{
    public string Street { get; set; }
}

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Friend>().OwnsOne(e => e.Address);
    modelBuilder.Entity<LessThanFriend>().OwnsOne(e => e.Address);
}

This is ambiguous as to whether LessThanFriend.CityAddress should be mapped to allow inheritance such that either a CityAddress or a FullAddress could be persisted. Typically, we only map inheritance when both types are in the model. However, having both types in the model as Owned types on different entities perhaps does not have the same semantics--especially when thinking of them like complex types.

Based on triage discussion from #9536, we think we want to support both the simple mapping (just persisting given concrete type, which is what the request on #9536 is for) and the inheritance mapping, which would require, for TPH, and additional discriminator column in the table. We did not come to a final decision on which should be the default, or what the new API will look like to switch between the two.

We would need API on ReferenceOwnershipBuilder to declare the derived types.
Related to #10140

It took me so much time to get to this issue.

I am having a problem in which a owned type generates a Discriminator property, even though there is no need for it, since the class that has this property is not derived anywhere else.

Can this be the same issue?

I tried removing it from migration and from the snapshot to test, but it generates a wrong sql statement when acessing the DbContext on that Set.

Is there any way to get around this, without generating the property on the database?

@andre-f-paggi

@andre-f-paggi Please file a new issue and include a runnable project/solution or complete code listing that demonstrates the behavior you are seeing.

@ajcvickers

@ajcvickers I can look at supplying a runnable solution if it will assist getting it resolved quicker

@chris-stormideas

@chris-stormideas We understand what this issue is about--i.e. inheritance mapping into a shared table is not supported. The feature is currently on the backlog, and not considered very high priority. The best way to influence getting it resolved is probably to make a case for why this specific mapping is so important.

@ajcvickers

@ajcvickers

What about collections of owned types, where the owned-collection is polymorphic?
For example:

public class Order
{
    public List<Position> Positions { get; set; } // Owned collection
}

public abstract class Position
{ }

public class FancyPosition : Position
{ }

public class StandardPosition : Position
{ }

public class SampleContext : DbContext
{
    public virtual DbSet<Order> Orders { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        modelBuilder.Entity<Order>().OwnsMany(p => p.Positions);
    }
}

Is this implicitly tracked by this issue or would you recommend creating a new issue for this?

@AndriySvyryd

@AndriySvyryd Thoughts on polymorphic owned collections?

Polymorphic owned collections will be covered by this, but similar to non-collections all derived types will need to be configured explicitly.

Polymorphic owned collections do provide the ability to compose our object model which is really quite nice.
From my perspective having to define all the derived types explicitly isn't a problem at all.
Do you guys have an idea when this issue might bubble up in the backlog?

I have a project I have been waiting to migrate over to efcore that currently uses Horrible InHouse Awful ORM (tm) that I wrote years ago much to today me's regret. This is the only feature left that I cant really support with efcore.

@digitalpowers

@digitalpowers For now we can only say that it won't happen this year.

Thanks for the feedback. If polymorphic owned collections are covered by this issue, I would recommend updating the issue title+description so that users can find this. ATM it is not really clear and looks like it only covers inline owned types. Thanks!

@AndriySvyryd

@AndriySvyryd Does this issue also cover the case where I explicitly want to set a HasDiscriminator under an owned entity?

Example:


            builder.OwnsOne<AlertPattern>("Pattern", b =>
            {
                b.HasDiscriminator<int>("type")
                    .HasValue<PatternOne>(1)
                    .HasValue<PatternTwo>(2)
                    .HasValue<PatternThree>(3)
                    .HasValue<PatternFour>(4)
                    .HasValue<PatternFive>(5);
            });

In this particular example, AlertPattern is an abstract class and PatternOne and friends inherit it.

is any input needed to help decide if this makes the cut for the current release? It is still the only thing preventing me from migrating to efcore and I very much want to :)

What's the chance we might see this in EF Core 9?

@chrisc-ona None - 9 is done

@ErikEJ

@ErikEJ well hopefully we'll have it in 10 then

Are there any updates regarding this topic ? I feel like this feature is missing so much, specially today when usage of DDD becoming more and more popular. I really looking forward to see this feature in EF core 10 !

Is there any chance to see this in ef core 11 ?

@ricoprzybylski

@ricoprzybylski No, we are still resource constrained. I doubt this could be done before EF 13

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Support inheritance for owned/property bag/shared-type entity types #9630

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Support inheritance for owned/property bag/shared-type entity types #9630

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AndriySvyryd commented on Jan 31, 2018

andre-f-paggi commented on Sep 17, 2018

ajcvickers commented on Sep 17, 2018

chris-stormideas commented on Feb 28, 2019

ajcvickers commented on Feb 28, 2019

davidroth commented on Jan 16, 2020

ajcvickers commented on Jan 16, 2020

AndriySvyryd commented on Jan 16, 2020

digitalpowers commented on Jan 17, 2020

AndriySvyryd commented on Jan 17, 2020

davidroth commented on Jan 17, 2020

Lobosque commented on Aug 25, 2020

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AndriySvyryd commented on Feb 13, 2026

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