Avoid default activerecord primary index creation <p>I am trying to workout how to advise/tell activerecord not to create it's primary index by default.</p> <p>Anyone know how i can achieve this ?</p> <pre><code>class CreateHouse &lt; ActiveRecord::Migration def change create_table :houses do |table| table.string :name, :null =&gt; false, :unique =&gt; true table.integer :number, :null =&gt; false, :unique =&gt; true table.string :category, :null =&gt; false table.timestamps(:null =&gt; false) end add_index :houses, [:category, :number], :unique =&gt; true end end </code></pre> <p>THANKS</p>