diff --git a/app/models/quantity.rb b/app/models/quantity.rb
index ed81124..e8d36d3 100644
--- a/app/models/quantity.rb
+++ b/app/models/quantity.rb
@@ -15,8 +15,8 @@ class Quantity < ApplicationRecord
     errors.add(:parent, :descendant_reference) if ancestor_of?(parent)
   end
   validates :name, presence: true, uniqueness: {scope: [:user_id, :parent_id]},
-    length: {maximum: type_for_attribute(:name).limit}
-  validates :description, length: {maximum: type_for_attribute(:description).limit}
+    length: {maximum: type_for_attribute(:name).limit || Float::INFINITY}
+  validates :description, length: {maximum: type_for_attribute(:description).limit || Float::INFINITY}
 
   # Update :depths of progenies after parent change
   before_save if: :parent_changed? do
@@ -61,18 +61,26 @@ class Quantity < ApplicationRecord
 
   # Return: ordered [sub]hierarchy
   scope :ordered, ->(root: nil, include_root: true) {
-    numbered = Arel::Table.new('numbered')
-
-    self.model.with(numbered: numbered(:parent_id, :name)).with_recursive(arel_table.name => [
-      numbered.project(
-        numbered[Arel.star],
-        numbered.cast(numbered[:child_number], 'BINARY').as('path')
-      ).where(numbered[root && include_root ? :id : :parent_id].eq(root)),
-      numbered.project(
-        numbered[Arel.star],
-        arel_table[:path].concat(numbered[:child_number])
-      ).join(arel_table).on(numbered[:parent_id].eq(arel_table[:id]))
-    ]).order(arel_table[:path])
+    if connection.adapter_name =~ /mysql/i
+      numbered = Arel::Table.new('numbered')
+      self.model.with(numbered: numbered(:parent_id, :name)).with_recursive(arel_table.name => [
+        numbered.project(
+          numbered[Arel.star],
+          numbered.cast(numbered[:child_number], 'BINARY').as('path')
+        ).where(numbered[root && include_root ? :id : :parent_id].eq(root)),
+        numbered.project(
+          numbered[Arel.star],
+          arel_table[:path].concat(numbered[:child_number])
+        ).join(arel_table).on(numbered[:parent_id].eq(arel_table[:id]))
+      ]).order(arel_table[:path])
+    elsif root.nil?
+      # SQLite: pathname column already stores the full hierarchical path
+      order(:pathname)
+    else
+      root_pathname = unscoped.where(id: root).pick(:pathname)
+      scope = order(:pathname).where("pathname LIKE ?", "#{root_pathname}#{PATHNAME_DELIMITER}%")
+      include_root ? scope.or(where(id: root)) : scope
+    end
   }
 
   # TODO: extract named functions to custom Arel extension