712 add priority rank to category_relationship table. Return categori…

…es in order on category#subcategories action

app/controllers/categories_controller.rb

@@ -7,7 +7,18 @@ def show
   end
 
   def subcategories
-    categories = Category.where("id in (select child_id from category_relationships where parent_id=?)", params[:id])
+    # Fetch category children records. Records are ordered by (optional) child_priority_rank
+    category_relationships = CategoryRelationship.where(parent_id: params[:id])
+                                                 .order(:child_priority_rank)
+                                                 .select(:child_id, :child_priority_rank)
+
+    child_ids = category_relationships.pluck(:child_id)
+
+    # Query categories using child_ids and order by child_priority_rank
+    categories = Category.joins("INNER JOIN (#{category_relationships.to_sql}) cr ON categories.id = cr.child_id")
+                         .where(id: child_ids)
+                         .order("cr.child_priority_rank")
+
     render json: CategoryPresenter.present(categories)
   end
 

db/migrate/20230609201040_add_child_priority_rank_column_to_category_relationships.rb

@@ -0,0 +1,6 @@
+class AddChildPriorityRankColumnToCategoryRelationships < ActiveRecord::Migration[6.1]
+  def change
+    add_column :category_relationships, :child_priority_rank, :integer
+    add_index(:category_relationships, [:child_id, :parent_id], :unique => true)
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2023_05_30_212331) do
+ActiveRecord::Schema.define(version: 2023_06_09_201040) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -117,6 +117,8 @@
   create_table "category_relationships", id: false, force: :cascade do |t|
     t.integer "parent_id", null: false
     t.integer "child_id", null: false
+    t.integer "child_priority_rank"
+    t.index ["child_id", "parent_id"], name: "index_category_relationships_on_child_id_and_parent_id", unique: true
   end
 
   create_table "change_requests", force: :cascade do |t|