Ash Elixir•3y ago

Sorting on a field in a relation

I tried the solution from https://discordapp.com/channels/711271361523351632/1072944619169534063, but can't seem to get it to work. Am I missing something? tweet.ex

    read :feed do
      description "Get the feed of tweets for a user"

      argument :user_id, :uuid do
        allow_nil? false
      end

      prepare build(load: [:items], sort: [item_order: :asc])

      filter expr(visible_to(user_id: arg(:user_id)))
    end
-----------------
  relationships do
    has_many :items, Tweet.Tweets.Item
  end
---------------
  aggregates do
    first :item_order, :items, :row_order

    read :feed do
      description "Get the feed of tweets for a user"

      argument :user_id, :uuid do
        allow_nil? false
      end

      prepare build(load: [:items], sort: [item_order: :asc])

      filter expr(visible_to(user_id: arg(:user_id)))
    end
-----------------
  relationships do
    has_many :items, Tweet.Tweets.Item
  end
---------------
  aggregates do
    first :item_order, :items, :row_order

item.ex

  attributes do
    attribute :row_order, :integer do
      allow_nil? true
    end

  attributes do
    attribute :row_order, :integer do
      allow_nil? true
    end

liveview file

  defp assign_twees(socket) do
    tweets =
      Tweets.Tweet.feed!(socket.assigns.current_user.id,
        load: tweet_load(socket.assigns.current_user)
      )

  ...

  defp tweet_load(current_user) do
    [
      :author_email,
      :author,
       items: [
        :sum_item_count,
      ]
    ]
  end

  defp assign_twees(socket) do
    tweets =
      Tweets.Tweet.feed!(socket.assigns.current_user.id,
        load: tweet_load(socket.assigns.current_user)
      )

  ...

  defp tweet_load(current_user) do
    [
      :author_email,
      :author,
       items: [
        :sum_item_count,
      ]
    ]
  end

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15 Replies

ZachDaniel•3y ago

That looks right to me, what is the error/stack trace you’re seeing?

jasono•3y ago

No error. Just doesn't sort it in the expected order. I will keep looking. Thanks!

ZachDaniel•3y ago

huh, that is strange. Would be good to look at the SQL logs to see what its doing wrong?

jasono•3y ago

Okay will do

JasonOP•3y ago

I realized my use case is different from the post referrenced above, so the aggregation first won't work. tweets has many items and the items need to be ordered by the value of its row_order field. Feels like this is a common use case, but I can't seem to find the related documentation. The current output looks like the following, but I'm trying to get the items to be listed in the ascending order. (ie. row_order 1, 3, 5, rather than 1, 5 ,3 )

Tweets.Tweet<
   ...
   item_order: 1,
   author_email: ...
   items: [
       Tweets.Item<
          row_order: 1
          ...
        Tweets.Item<
          row_order: 5
           ...
        Tweets.Item<
          row_order: 3
           ...

Tweets.Tweet<
   ...
   item_order: 1,
   author_email: ...
   items: [
       Tweets.Item<
          row_order: 1
          ...
        Tweets.Item<
          row_order: 5
           ...
        Tweets.Item<
          row_order: 3
           ...

ZachDaniel•3y ago

you would load them with a query load(stuff, items: Ash.Query.sort(Item, row_order: :asc))

JasonOP•3y ago

Thanks! This seems to work.

    read :feed do
      prepare build(
                load: [items: Ash.Query.sort(Item, row_order: :asc)],
                sort: [inserted_at: :desc]
              )

    read :feed do
      prepare build(
                load: [items: Ash.Query.sort(Item, row_order: :asc)],
                sort: [inserted_at: :desc]
              )

but not this. Is there. (the load part appears to be added to the load setting defined in the action feed) What's the right way to write it?

Tweets.Tweet.feed!(socket.assigns.current_user.id,
        load: tweet_load(socket.assigns.current_user)

 defp tweet_load(current_user) do
    [
       :like_count,
      items: [
        :item_remaining_count,
        Ash.Query.sort(Item, row_order: :asc)
       ]

    ]
  end

Tweets.Tweet.feed!(socket.assigns.current_user.id,
        load: tweet_load(socket.assigns.current_user)

 defp tweet_load(current_user) do
    [
       :like_count,
      items: [
        :item_remaining_count,
        Ash.Query.sort(Item, row_order: :asc)
       ]

    ]
  end

ZachDaniel•3y ago

Either one should work actually…but try making it a single query I.e items: Ash.Query.sort(…) |> Ash.Query.load(…)

JasonOP•3y ago

The top one actually works. It's the bottom one I'm trying to get to work. Even if I change it to this, by removing :like_count ,

 defp tweet_load(current_user) do
    [
      items: [
        Ash.Query.sort(Item, row_order: :asc)
       ]

    ]
  end

 defp tweet_load(current_user) do
    [
      items: [
        Ash.Query.sort(Item, row_order: :asc)
       ]

    ]
  end

` I still get this error

Input Invalid
* #Ash.Query<resource: Tweets.Item, sort: [row_order: :asc]> is not a valid load
    at items, load

Input Invalid
* #Ash.Query<resource: Tweets.Item, sort: [row_order: :asc]> is not a valid load
    at items, load

ZachDaniel•3y ago

Try removing it from the list, sorry Need to work on the accepted formats there Like items: query

JasonOP•3y ago

But if I remove it from the list(but leave other attributes/calculations to load), sorting doesn't take effect even if it's defined in the action. Looks like load in Tweets.Tweet.get_by_id(user_id, load: ....) overrides the build( load inside the action.

 defp tweet_load(current_user) do
    [
       :like_count,
      items: [
        :item_remaining_count
       ]

    ]
  end

 defp tweet_load(current_user) do
    [
       :like_count,
      items: [
        :item_remaining_count
       ]

    ]
  end

ZachDaniel•3y ago

Sorry, here is what I mean

 defp tweet_load(current_user) do
    [
       :like_count,
      items: Ash.Query.sort(Item, row_order: :asc)
    ]
  end

 defp tweet_load(current_user) do
    [
       :like_count,
      items: Ash.Query.sort(Item, row_order: :asc)
    ]
  end

JasonOP•3y ago

how do I add attribute/calculation to it? Is something like this allowed?

 defp tweet_load(current_user) do
    [
       :like_count,
      items: Ash.Query.sort(Item, row_order: :asc),
            [:item_remaining_count]
    ]
  end

 defp tweet_load(current_user) do
    [
       :like_count,
      items: Ash.Query.sort(Item, row_order: :asc),
            [:item_remaining_count]
    ]
  end

ZachDaniel•3y ago

 defp tweet_load(current_user) do
    items = Item |> Ash.Query.sort(row_order: :asc) |> Ash.Query.load(:item_remaining_count)
    
    [
       :like_count,
      items: items
    ]
  end

 defp tweet_load(current_user) do
    items = Item |> Ash.Query.sort(row_order: :asc) |> Ash.Query.load(:item_remaining_count)
    
    [
       :like_count,
      items: items
    ]
  end

JasonOP•3y ago

Ahh... okay. thanks!

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Sorting on a field in a relation

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