Help with how to use schema and embedded schema

Questions / Help
, ,
1

So this is my first time using embedded schema and I’m having an issue finding information to help me work through how to handle what I need to do in my app.

Basically, a company has the option to white label their site. We’re storing their white label configurations in an embedded schema that we can pull into our front-end applications.

As of now we’re storing the white label information in a white label table in our database and each configuration belongs to a company. I’m unsure of how to handle creating and updating the embedded schema.

defmodule App.WhiteLabels.WhiteLabel do
  @moduledoc false

  use Ecto.Schema
  import Ecto.Changese

  schema "white_labels" do
    field(:subdomain, :string)
    belongs_to(:company, App.Companys.Company
      foreign_key: :company_id
    )
    embeds_one(:themes, App.WhiteLabels.Theme)
    timestamps()
  end

  @doc false
  @spec changeset(%__MODULE__{}, map) :: %Ecto.Changeset{}
  def changeset(schema, attrs) do
    schema
    |> cast(attrs, [:subdomain, :company_id])
    |> validate_required([:subdomain, :company_id])
    |> cast_embed(:themes, required: true)
  end

defmodule App.WhiteLabels.Theme do
  @moduledoc false

  use Ecto.Schema
  import Ecto.Changeset

  embedded_schema do
    field :logo, :string
    field :logo_alt, :string
    field :favicon, :string
    field :background, :string
    field :header_background, :string
    field :header_text, :string
    field :title, :string
    field :text, :string
  end

  @fields [
    :logo,
    :logo_alt,
    :favicon,
    :background,
    :header_background,
    :header_text,
    :title,
    :text,
  ]

  @doc false
  @spec changeset(%__MODULE__{}, map) :: %Ecto.Changeset{}
  def changeset(schema, attrs) do
    schema
    |> cast(attrs, @fields)
  end
end

How would I create a new white label when I need to create %WhiteList{} and %Theme{} at the same time? Does this make sense? Most of the examples I find are adding new embedded schema data to already created data or updating an embedded schema.

1 Like
2

Not an Ecto expert:) So I guess somewhere in your Context you have:

%WhiteLabel{}
|> WhiteLabel.changeset(attrs)
|> Repo.insert()

and you send the “themes” data alongside the subdomain. Doesn’t that work? What problem are you encountering? What is the structure of the data you are sending to the WhiteLabel changeset function (can you IO.inspect it)?

2 Likes
3

Hi,

In my personal current learning path, I don’t yet reach advanced topic like embedded schema (and I even didn’t hear of it until now).

But I already had to deal with similar concern and JSON (or JSONB) field in Postgres works like a charm.
But I admit that (at least when I did it in rails) it was painful to do validation (and even casting values)
IIRC latest version of Rails and Active Records allow virtual attributes but anyway it was somehow difficult to maintain.

But I guess (I mean I hope) that Ecto Changeset can deal easily with store fields in Postgres thanks to cast, or I might be wrong…

BTW interesting to see how you’ll deal with that.
Good luck in the meantime.

4

I think you should correct :themes to :theme. Since you are using plural and you are not supplying extra options then Ecto could be tripped up.

1 Like
5

You’re right, currently I have the following when creating a White Label:

    %WhiteLabel{}
    |> WhiteLabel.changeset(attrs)
    |> Repo.insert()

With what you’re saying I should be fine passing in attrs that look like the following:

    attrs = %{
      company_id: 1,
      subdomain: "acme-corp",
      theme: %{
        logo: "https://image.logo.jpg"
        logo_alt: "Company Logo",
        favicon: "https://image.favicon.favicon.jpg",
        background: "https://image.background.jpg",
        header_background: "#212121",
        header_text: '#FFF',
        title: '#212121',
        text: '#212121'
      }
    }
6

So is it :theme or :themes? The schema field says :themes and in your attrs I see :theme.
And what is the error/result?

7

I am going to change :themes to :theme I think as per the comment by @dimitarvp

Sorry I meant to add that in my reply. I’m going to run this now and see what result I get.

8

Works well!

Create white label:

    attrs = %{
      company_id: 1,
      subdomain: "acme-corp",
      theme: %{
        logo: "https://image.logo.jpg"
        logo_alt: "Company Logo",
        favicon: "https://image.favicon.favicon.jpg",
        background: "https://image.background.jpg",
        header_background: "#212121",
        header_text: '#FFF',
        title: '#212121',
        text: '#212121'
      }
    }

    %WhiteLabel{}
    |> WhiteLabel.changeset(attrs)
    |> Repo.insert()
1 Like
9

Glad to hear you made it work.

Let’s be clear: you are free to use whatever names and break conventions – but you’ll have to specify more attributes (configuration) if you do so. That’s why your initial code didn’t work – you didn’t give Ecto the extra configuration options that it expected since your name implied one-to-many association.

You can take a look at Ecto.Schema docs and take it from there (for the future).

Also consider marking one of the comments (yours included) as an accepted answer. It will help future readers.

1 Like