title: Unique taxonomy input in wordpress
body: <p>I have registered a taxonomy named " sku " in my wordpress function.php.</p>
  
  <pre><code>register_taxonomy( 'sku', 'post', array( 'hierarchical' =&gt; false,  'label' =&gt; 'SKU', 'query_var' =&gt; false, 'rewrite' =&gt; true,'public' =&gt; true,'show_ui' =&gt; true,'revisions' =&gt; false,'publicly_queryable' =&gt; true,'exclude_from_search' =&gt; false,'show_in_nav_menus' =&gt; true ));
  </code></pre>
  
  <p>But I want to input a unique sku value for each post. Please somebody give me a solution how can I make it ?</p>