Change variable names

Author: yzhoubk

db/migrate/20250930230620_update_fix_term_item_relation.rb

@@ -1,42 +1,42 @@
 class UpdateFixTermItemRelation < ActiveRecord::Migration[7.0]
   def up
+    after_1999_id = select_value("SELECT id FROM terms WHERE value = 'After 1999'")
+    after_2000_id = select_value("SELECT id FROM terms WHERE value = 'After 2020'")
+    return unless after_1999_id && after_2000_id
+    
     execute <<~SQL.squish
-      old_id = select_value("SELECT id FROM terms WHERE value = 'After 1999'")
-      new_id = select_value("SELECT id FROM terms WHERE value = 'After 2020'")
-      return unless old_id && new_id
-
       WITH target AS (
         SELECT it.term_id, it.item_id
         FROM items i
         JOIN items_terms it ON i.id = it.item_id
         JOIN terms t ON it.term_id = t.id
-        WHERE t.id = #{old_id}
+        WHERE t.id = #{after_1999_id}
           AND i.date = '[2020]'
       )
       UPDATE items_terms it
-      SET term_id = #{new_id}
+      SET term_id = #{after_2000_id}
       FROM target
       WHERE it.item_id = target.item_id
       AND it.term_id = target.term_id;
     SQL
   end
 
-  def up
-     new_id = select_value("SELECT id FROM terms WHERE value = 'After 1999'")
-     old_id = select_value("SELECT id FROM terms WHERE value = 'After 2020'")
-      return unless old_id && new_id
+  def down
+    after_1999_id = select_value("SELECT id FROM terms WHERE value = 'After 1999'")
+    after_2000_id = select_value("SELECT id FROM terms WHERE value = 'After 2020'")
+    return unless after_1999_id && after_2000_id
 
     execute <<~SQL.squish
       WITH target AS (
         SELECT it.term_id, it.item_id
         FROM items i
         JOIN items_terms it ON i.id = it.item_id
         JOIN terms t ON it.term_id = t.id
-        WHERE t.id = #{old_id}
+        WHERE t.id = #{after_2000_id}
           AND i.date = '[2020]'
       )
       UPDATE items_terms it
-      SET term_id = #{new_id}
+      SET term_id = #{after_1999_id}
       FROM target
       WHERE it.item_id = target.item_id
       AND it.term_id = target.term_id;