Merge pull request #19153 from stephenminded/docs_fix_polymorphic_index

[docs fix] Indexing a polymorphic assoc adds index on type and id
rails · Mar 1, 2015 · 1d10b4b · 1d10b4b
2 parents edbcdb9 + 683ad0b
commit 1d10b4b
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/guides/source/association_basics.md b/guides/source/association_basics.md
@@ -460,7 +460,7 @@ class CreatePictures < ActiveRecord::Migration
       t.timestamps null: false
     end
 
-    add_index :pictures, :imageable_id
+    add_index :pictures, [:imageable_id, :imageable_type]
   end
 end
 ```