12 replies

Using no attributes to use a parent_type / parent_id style table as a join table

I have this table:

attributes do
    integer_primary_key :id

    attribute :target_type, Safari.Types.LithostratTargetType, public?: true, allow_nil?: false
    attribute :target_id, :integer, public?: true, allow_nil?: false
    create_timestamp :inserted_at, public?: true
    update_timestamp :updated_at, public?: true
  end

  relationships do
    belongs_to :parent, Safari.Outcrop.Outcrop, public?: true, allow_nil?: false

    has_one :group, Safari.Wiki.Group,
      source_attribute: :target_id,
      destination_attribute: :id,
      filter: expr(parent(target_type) == :group)

    has_one :formation, Safari.Wiki.Formation,
      source_attribute: :target_id,
      destination_attribute: :id,
      filter: expr(parent(target_type) == :formation)

    has_one :member, Safari.Wiki.Member,
      source_attribute: :target_id,
      destination_attribute: :id,
      filter: expr(parent(target_type) == :member)
  end

attributes do
    integer_primary_key :id

    attribute :target_type, Safari.Types.LithostratTargetType, public?: true, allow_nil?: false
    attribute :target_id, :integer, public?: true, allow_nil?: false
    create_timestamp :inserted_at, public?: true
    update_timestamp :updated_at, public?: true
  end

  relationships do
    belongs_to :parent, Safari.Outcrop.Outcrop, public?: true, allow_nil?: false

    has_one :group, Safari.Wiki.Group,
      source_attribute: :target_id,
      destination_attribute: :id,
      filter: expr(parent(target_type) == :group)

    has_one :formation, Safari.Wiki.Formation,
      source_attribute: :target_id,
      destination_attribute: :id,
      filter: expr(parent(target_type) == :formation)

    has_one :member, Safari.Wiki.Member,
      source_attribute: :target_id,
      destination_attribute: :id,
      filter: expr(parent(target_type) == :member)
  end

And in Group I want to query all Outcrop through this table..

I thought I had done this before and I am currently stuck here (in

relationships

relationships

Group

Group

has_many :outcrops, Outcrop do
      no_attributes? true
      filter expr(what_to_put_here.target_id == parent(id) and target_type == :group)
    end

has_many :outcrops, Outcrop do
      no_attributes? true
      filter expr(what_to_put_here.target_id == parent(id) and target_type == :group)
    end

Solution

Ok for anyone else coming across this post because they want to use no_attributes? true to do some complex mapping, here is the gist of it:

- You can do a has_many or has_one to any App.Domain.Resource with some prereqs:
- There must be a tangible path mapped up back to what you want
- In my case I had
- Outcrop
- LithostratOutcropLink (with parent_id == outcrop, target_type == group|member|formation and target_id == the id of the group etc)
- Group
Solution to put on Group:

has_many :outcrops, Safari.Outcrop.Outcrop do
      no_attributes? true

      filter expr(
               lithostrat_outcrop_links.target_id == parent(id) and
                 lithostrat_outcrop_links.target_type == :group
             )
    end

has_many :outcrops, Safari.Outcrop.Outcrop do
      no_attributes? true

      filter expr(
               lithostrat_outcrop_links.target_id == parent(id) and
                 lithostrat_outcrop_links.target_type == :group
             )
    end

This works because outcrop has:

has_many :lithostrat_outcrop_links, LithostratOutcropLink,
      public?: true,
      destination_attribute: :parent_id

has_many :lithostrat_outcrop_links, LithostratOutcropLink,
      public?: true,
      destination_attribute: :parent_id

And that lets the filter traverse this relation and relate the ids etc with the source resource, using this middle table as an impromptu jointable.

Jump to solution

Ash Framework•9mo ago•

12 replies

Oliver

Using no attributes to use a parent_type / parent_id style table as a join table

I have this table:

attributes do
    integer_primary_key :id

    attribute :target_type, Safari.Types.LithostratTargetType, public?: true, allow_nil?: false
    attribute :target_id, :integer, public?: true, allow_nil?: false
    create_timestamp :inserted_at, public?: true
    update_timestamp :updated_at, public?: true
  end

  relationships do
    belongs_to :parent, Safari.Outcrop.Outcrop, public?: true, allow_nil?: false

    has_one :group, Safari.Wiki.Group,
      source_attribute: :target_id,
      destination_attribute: :id,
      filter: expr(parent(target_type) == :group)

    has_one :formation, Safari.Wiki.Formation,
      source_attribute: :target_id,
      destination_attribute: :id,
      filter: expr(parent(target_type) == :formation)

    has_one :member, Safari.Wiki.Member,
      source_attribute: :target_id,
      destination_attribute: :id,
      filter: expr(parent(target_type) == :member)
  end

attributes do
    integer_primary_key :id

    attribute :target_type, Safari.Types.LithostratTargetType, public?: true, allow_nil?: false
    attribute :target_id, :integer, public?: true, allow_nil?: false
    create_timestamp :inserted_at, public?: true
    update_timestamp :updated_at, public?: true
  end

  relationships do
    belongs_to :parent, Safari.Outcrop.Outcrop, public?: true, allow_nil?: false

    has_one :group, Safari.Wiki.Group,
      source_attribute: :target_id,
      destination_attribute: :id,
      filter: expr(parent(target_type) == :group)

    has_one :formation, Safari.Wiki.Formation,
      source_attribute: :target_id,
      destination_attribute: :id,
      filter: expr(parent(target_type) == :formation)

    has_one :member, Safari.Wiki.Member,
      source_attribute: :target_id,
      destination_attribute: :id,
      filter: expr(parent(target_type) == :member)
  end

And in Group I want to query all Outcrop through this table..

I thought I had done this before and I am currently stuck here (in

relationships

relationships

Group

Group

has_many :outcrops, Outcrop do
      no_attributes? true
      filter expr(what_to_put_here.target_id == parent(id) and target_type == :group)
    end

has_many :outcrops, Outcrop do
      no_attributes? true
      filter expr(what_to_put_here.target_id == parent(id) and target_type == :group)
    end

Solution

has_many :outcrops, Safari.Outcrop.Outcrop do
      no_attributes? true

      filter expr(
               lithostrat_outcrop_links.target_id == parent(id) and
                 lithostrat_outcrop_links.target_type == :group
             )
    end

has_many :outcrops, Safari.Outcrop.Outcrop do
      no_attributes? true

      filter expr(
               lithostrat_outcrop_links.target_id == parent(id) and
                 lithostrat_outcrop_links.target_type == :group
             )
    end

This works because outcrop has:

has_many :lithostrat_outcrop_links, LithostratOutcropLink,
      public?: true,
      destination_attribute: :parent_id

has_many :lithostrat_outcrop_links, LithostratOutcropLink,
      public?: true,
      destination_attribute: :parent_id

And that lets the filter traverse this relation and relate the ids etc with the source resource, using this middle table as an impromptu jointable.

Jump to solution

Using no attributes to use a parent_type / parent_id style table as a join table

Using no attributes to use a parent_type / parent_id style table as a join table

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