diff --git a/guides/source/association_basics.md b/guides/source/association_basics.md
index 8ef982f8c5..91b268d766 100644
--- a/guides/source/association_basics.md
+++ b/guides/source/association_basics.md
@@ -340,7 +340,7 @@ class CreateAssembliesAndParts < ActiveRecord::Migration
       t.timestamps
     end
 
-    create_table :assemblies_parts do |t|
+    create_table :assemblies_parts, id: false do |t|
       t.belongs_to :assembly
       t.belongs_to :part
     end