is it possible to store recursive data types as json column?

[darena-antonw]

Include your code

I have class that can contain it self or other types that can contain that same class, is it possible to store this type as json in a column with ef core?

I'd expect to have something like:

modelBuilder.Entity<Product>()
            .OwnsMany(
                x => x.Components,
                navBuilder => navBuilder.ToJsonTheWhoooooleDamnThing()
            );

instead I have to configure each navigation manually, but

• if configuring navigations of types which have already been configured - exception is thrown
• if not configuring these navigations data is incorrectly stored in the databse
• furthermore, included a screenshot, for some reason ef core attached the parent object to the child property

Sample:

using Microsoft.EntityFrameworkCore;

{
    var appDbContext = new AppDbContext();

    appDbContext.Database.EnsureDeleted();
    appDbContext.Database.EnsureCreated();

    appDbContext.Products.Add(new Product()
    {
        Name = "test",
        Components =
        [
            new Component() { Name = Guid.NewGuid().ToString() },
            new Component()
            {
                Side = new Component() { Name = Guid.NewGuid().ToString() },
                Name = Guid.NewGuid().ToString(),
            },
            new Component()
            {
                Name = Guid.NewGuid().ToString(),
                Components =
                [
                    new Component()
                    {
                        Name = Guid.NewGuid().ToString(),
                        Side = new Component() { Name = Guid.NewGuid().ToString(), Components = [] },
                    },
                    new Component() { Name = Guid.NewGuid().ToString() },
                    new Component() { Name = Guid.NewGuid().ToString() }
                ]
            },
        ],
    });

    appDbContext.SaveChanges();
}
{
    var appDbContext = new AppDbContext();
    var products = appDbContext.Products.ToList();

    Console.WriteLine(products);
}

public class AppDbContext : DbContext
{
    public DbSet<Product> Products { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseNpgsql("...");
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);

        modelBuilder.Entity<Product>()
            .OwnsMany(
                x => x.Components,
                navBuilder =>
                {
                    navBuilder.ToJson();
                    navBuilder.OwnsMany(x => x.Components);

                    // can't configure further, exception is thrown
                    // navBuilder.OwnsMany(x => x.Components, builder =>
                    // {
                    //     builder.OwnsMany(x => x.Components);
                    //     builder.OwnsOne(x => x.Side);
                    // });
                    
                    navBuilder.OwnsOne(x => x.Side);
                }
            );
    }
}


public class Product
{
    public int Id { get; set; }
    public string Name { get; set; }
    public List<Component> Components { get; set; }
}

public class Component
{
    public string Name { get; set; }
    public List<Component> Components { get; set; }
    public Component Side { get; set; }
}

Stored json:

[
  {
    "Name": "4741f8a5-b7eb-4f1a-ad89-67654d305199",
    "Side": null,
    "Components": null
  },
  {
    "Name": "8077e443-cdd3-4746-97fa-c40d33e12686",
    "Side": {
      "Name": "a35dc642-fe01-43fb-86f2-01c3b87f3734"
    },
    "Components": null
  },
  {
    "Name": "4651ee19-3215-46c0-9e20-0fafd62fbc25",
    "Side": null,
    "Components": [
      {
        "Name": "886583d3-4cca-4abf-87a0-65b8a41ab8e1"
      },
      {
        "Name": "6aa899eb-0d14-4ecf-9f1f-95c9b61d5620"
      },
      {
        "Name": "aeefadac-817f-44c1-84b0-d154423896ca"
      }
    ]
  }
]

retrieved data:

Include provider and version information

EF Core version: 8.0.2
Database provider: Npgsql.EntityFrameworkCore.PostgreSQL 8.0.2
Target framework: .NET 8.0
Operating system: 14.2.1 (23C71)
IDE: Rider 2024.1.1

[AndriySvyryd]

I have class that can contain it self or other types that can contain that same class, is it possible to store this type as json in a column with ef core?

Component references itself, so if we were to keep mapping it automatically it would go on forever.

Note to implementor: review naming logic for Product.Components.Components and invertedOwnership removal in InternalForeignKeyBuilder