diff --git a/db/migrate/20210212143002_add_missing_unique_indices.acts_as_taggable_on_engine.rb b/db/migrate/20210212143002_add_missing_unique_indices.acts_as_taggable_on_engine.rb
index 0d621815e..e17b2a52f 100644
--- a/db/migrate/20210212143002_add_missing_unique_indices.acts_as_taggable_on_engine.rb
+++ b/db/migrate/20210212143002_add_missing_unique_indices.acts_as_taggable_on_engine.rb
@@ -8,11 +8,15 @@ class AddMissingUniqueIndices < ActiveRecord::Migration; end
   def self.up
     add_index ActsAsTaggableOn.tags_table, :name, unique: true
 
-    remove_index ActsAsTaggableOn.taggings_table, :tag_id if index_exists?(ActsAsTaggableOn.taggings_table, :tag_id)
+    if index_exists?(ActsAsTaggableOn.taggings_table, :tag_id)
+      remove_foreign_key :taggings, :tags
+      remove_index ActsAsTaggableOn.taggings_table, :tag_id
+    end
     remove_index ActsAsTaggableOn.taggings_table, name: "taggings_taggable_context_idx"
     add_index ActsAsTaggableOn.taggings_table,
       [:tag_id, :taggable_id, :taggable_type, :context, :tagger_id, :tagger_type],
       unique: true, name: "taggings_idx"
+    add_foreign_key ActsAsTaggableOn.taggings_table, ActsAsTaggableOn.tags_table, column: 'tag_id'
   end
 
   def self.down