prevent user creating a duplicate node title

Question

how to prevent user creating a duplicate node title for a content type?

I already try uniqueness module (https://drupal.org/project/uniqueness) but it's only list out the duplicate content title but not return any error message when user save the new content. Any suggestion module or code? :)

Answer 1

You can try the Unique field module.

This module performs additional validation when a node is created or updated by a user to require that a node's title, author, language, and CCK fields are unique within a given context.

I have not tested it yet, but it seems promising.

Answer 2

We can think of two coding approaches:

1. Use hook_node_validate()

2. Call '#validate' in form alter

We should not validate inside hook_node_insert() or, hook_node_presave()

You can make use of code like below:

  $type = 'Content_Type_Machine_Name_You_Want_To_Validate_For';

  if (YOUR_CONDITION_FOR_CONTENT_TYPE_CHECK) {  
    $query = db_select('node', 'n');
    $node_title_exists =  $query->fields('n', array('nid'))
      ->condition('n.type', $type, '=')
      ->condition('n.title', 'SUBMITTED_NODE_TITLE', '=')
      ->execute()
      ->fetchField();
    if ($node_title_exists) {
      // WRITE form_set_error();    
    }
  }

Hope it helps

Answer 3

What you are looking for is node title validation https://www.drupal.org/project/node_title_validation