adding data to the junction table

How can i add data to a junction/pivot table through a form? I have create action enabled on the junction table

21 Replies

AshPhoenix has some great tooling around that. Please read the docs carefully, because AshPhoenix Forms function a bit differently than Ecto changesets. https://hexdocs.pm/ash_phoenix/AshPhoenix.Form.html#module-working-with-related-data

talha-azeemOP•3y ago

I did read it but i couldn't get much out of it. That is why i came to support channel

frankdugan3•3y ago

Could you expand a little bit? What did you try, what part of it is confusing specifically?

ZachDaniel•3y ago

You'll want to look at these docs as well: https://hexdocs.pm/ash/Ash.Changeset.html#manage_relationship/4 Before you try to do it with a form, get it working by calling actions

talha-azeemOP•3y ago

Is it something like cast_assoc?

ZachDaniel•3y ago

Yes It works similarly but there are a lot more options/instructions

talha-azeemOP•3y ago

is there any example in ash-hq?

ZachDaniel•3y ago

Nope For instance, one of your options might be something like this:

# {:create, destination_action_name, :join_action_name, [:fields, :for, :join]}
on_no_match: {:create, :create, :create, [:list, :of, :join_table, :params]}

# {:create, destination_action_name, :join_action_name, [:fields, :for, :join]}
on_no_match: {:create, :create, :create, [:list, :of, :join_table, :params]}

That would create a destination record, and a join record, passing certain options to the join resource action

talha-azeemOP•3y ago

I have three tables at the moment. Teams, Users, Team Joined User(junction table) many_to_many relation is defined in teams and users. this is what i have done so far. for this implementation. What i was trying to achieve here was to have a dropdown of user that gets selected and then have a hidden input of team_idand insert it in the junction table but it gives me this in form submit_errors: [team: {"is required", []}, user: {"is required", []}]

form =
  user
  |> AshPhoenix.Form.for_update(:update,
    api: MyApi,
    forms: [
      profile: [
        resource: MyApp.Profile,
        data: user.profile,
        create_action: :create,
        update_action: :update
        forms: [
          emails: [
            data: user.profile.emails,
            resource: MyApp.UserEmail,
            create_action: :create,
            update_action: :update
          ]
        ]
      ]
    ])

form =
  user
  |> AshPhoenix.Form.for_update(:update,
    api: MyApi,
    forms: [
      profile: [
        resource: MyApp.Profile,
        data: user.profile,
        create_action: :create,
        update_action: :update
        forms: [
          emails: [
            data: user.profile.emails,
            resource: MyApp.UserEmail,
            create_action: :create,
            update_action: :update
          ]
        ]
      ]
    ])

Do i need to define the form like this instead of normal create one for teamjoineduser? I am not getting it 😅

ZachDaniel•3y ago

Have you read the entirety of the documentation about manage_relationship

talha-azeemOP•3y ago

yeah i am reading it as we talk.

frankdugan3•3y ago

In a nutshell, you're going to create a custom action that 1) accepts args for the relationships, and 2) configure manage_relationship for that action. Then you can use that custom action in the form. Then you can use forms: [auto?: true] and it will be a lot simpler, IMO.

talha-azeemOP•3y ago

@frankdugan3 action will be defined like we defined code_interface, right?

frankdugan3•3y ago

This is not a many to many, just an example of the kind of thing you'd do:

    create :create do
      primary? true
      argument :type_id, :uuid, allow_nil?: false
      argument :employee_id, :uuid, allow_nil?: false

      change manage_relationship(:type_id, :type, type: :append_and_remove)
      change manage_relationship(:employee_id, :employee, type: :append_and_remove)
    end

    create :create do
      primary? true
      argument :type_id, :uuid, allow_nil?: false
      argument :employee_id, :uuid, allow_nil?: false

      change manage_relationship(:type_id, :type, type: :append_and_remove)
      change manage_relationship(:employee_id, :employee, type: :append_and_remove)
    end

talha-azeemOP•3y ago

okay, i think i get it a little. it will be defined in my junction table resource, right?

frankdugan3•3y ago

Then, that gives AshPhoenix the info it needs to do this instead:

form =
  user
  |> AshPhoenix.Form.for_update(:update,
    api: MyApi,
    forms: [auto?: true]

form =
  user
  |> AshPhoenix.Form.for_update(:update,
    api: MyApi,
    forms: [auto?: true]

Much easier to grep.

talha-azeemOP•3y ago

I will try it in the morning. Thank you. in the above action i defined it for create and in here you said Form.for_update?

create :create do
      primary? true
      argument :team_id, :uuid, allow_nil?: false
      argument :user_id, :uuid, allow_nil?: false

      change manage_relationship(:team_id, :team, type: :append_and_remove)
      change manage_relationship(:user_id, :user, type: :append_and_remove)
    end


identities do
    identity :unique_team_joined, [:user_id, :team_id]
  end

create :create do
      primary? true
      argument :team_id, :uuid, allow_nil?: false
      argument :user_id, :uuid, allow_nil?: false

      change manage_relationship(:team_id, :team, type: :append_and_remove)
      change manage_relationship(:user_id, :user, type: :append_and_remove)
    end


identities do
    identity :unique_team_joined, [:user_id, :team_id]
  end

Defined this in team joined user resource. now it works but two insertions are going at same time I think I am missing something here. @Zach Daniel just wondering which extension you are using for autocomplete in ASH resource? P.s. I just saw your twitter video and you showed the many_to_many relation through the ash admin 😅 I used a different approach for this. After looking at the twitter repo by @Zach Daniel . I made my junction table attributes attribute_writable? true and then added this create action:

create :create do
      primary? true
      upsert? true
      upsert_identity :unique_team_joined
    end

create :create do
      primary? true
      upsert? true
      upsert_identity :unique_team_joined
    end

and now it works for me.

ZachDaniel•3y ago

🤔 you just wanted to be able to create an instance of the join table? TBH I still don’t really understand exactly what you were trying to do, but I’m glad you got it worked out 👍

talha-azeemOP•3y ago

basically, i had three tables 1. users 2. teams 3. team joined user (junction table) I wanted to make an addition to junction table through the form.

ZachDaniel•3y ago

And did you get it worked out with [auto?: true] forms?

talha-azeemOP•3y ago

yes it is working now

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