Display last record in database using Phoenix/Ecto

Question

This is such a basic question that I'm failing to find the details online.

I have a model called 'Radios' and I wish to display the last radio added on to my home page - templates/page/index.html.eex

What I have so far:

radio.ex

defmodule Radios.Radio do
  use Radios.Web, :model
  import Ecto.Query

  schema "radios" do
    field :name, :string
    field :desc, :string
    field :price, :integer
    field :text1, :string
    field :text2, :string
    field :text3, :string
    field :text4, :string
    field :mainimg, :string

    timestamps()
  end

  @doc """
  Builds a changeset based on the `struct` and `params`.
  """
  def changeset(struct, params \\ %{}) do
    struct
    |> cast(params, [:name, :desc, :price, :text1, :text2, :text3, :text4, :mainimg])
    |> validate_required([:name, :desc, :price, :text1, :text2, :mainimg])
  end

  def sorted(query) do
    from r in query,
    order_by: [desc: r.inserted_at]
  end

end

page_controller.ex

defmodule Radios.PageController do
  use Radios.Web, :controller

  alias Radios.Radio


  def index(conn, _params) do
    last_radio = Radio
    |> Radio.sorted
    |> Radios.Repo.one
    render(conn, "index.html", radio: radio)

  end
end

Page Template

<p class="title is-4"><%= @last_radio.name %></p>

I'm assuming I should be writing the query in page controller and not the radio controller?

All of this results in the following console error:

== Compilation error on file web/controllers/page_controller.ex ==
** (CompileError) web/controllers/page_controller.ex:11: undefined function radio/0

This is probably soooo basic, and imagine I'm missing something very simple, but what!?

Justin Wood Justin Wood · Accepted Answer · 2017-05-03T14:45:08

def index(conn, _params) do
  last_radio = Radio
    |> Radio.sorted
    |> Radios.Repo.one
  render(conn, "index.html", radio: radio)
end

You are assigning the result of your query to last_radio, but then you are trying to use the variable radio when you assign it in your render. I believe you will want

render(conn, "index.html", last_radio: last_radio)

instead.

Display last record in database using Phoenix/Ecto

1 Answers