function message_update_7013 in Message 7

message.mid is part of the primary key but is not specified to be 'not null'.

File

./message.install, line 537

Install, update, and uninstall functions for the message module.

Code

function message_update_7013() {

  // Here we have some special concern:
  // 1. Keep the field as serial so the auto_increment will not affected.
  // 2. Before setting (or change) a field as serial PK should be dropped.
  // 3. BTW, if change a serial field without any index will fail in MySQL.
  // Let's add a temporary unique key for mid so MySQL will let it go.
  db_add_unique_key('message', 'temp_key', array(
    'mid',
  ));

  // Now remove the PK before changing a field as serial (well, even it is
  // already a serial field, originally).
  db_drop_primary_key('message');

  // Here we can successfully alter the serial field without error message.
  // See https://api.drupal.org/api/drupal/includes!database!database.inc/function/db_change_field/7
  db_change_field('message', 'mid', 'mid', array(
    'type' => 'serial',
    'unsigned' => TRUE,
    'description' => 'The Unique ID of the message.',
    'not null' => TRUE,
  ), array(
    'primary key' => array(
      'mid',
    ),
  ));

  // Finally, remove the temporary unique key because no longer useful.
  db_drop_unique_key('message', 'temp_key');
}