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Definition

db_connect($url)
drupal/includes/database.mysqli.inc, line 54

Description

Initialise a database connection.

Note that mysqli does not support persistent connections.

Related topics

Name	Description
Database abstraction layer	Allow the use of different database servers using the same code base.

Code

function db_connect($url) {
  // Check if MySQLi support is present in PHP
  if (!function_exists('mysqli_init') && !extension_loaded('mysqli')) {
    drupal_maintenance_theme();
    drupal_set_header('HTTP/1.1 503 Service Unavailable');
    drupal_set_title('PHP MySQLi support not enabled');
    print theme('maintenance_page', '<p>We were unable to use the MySQLi database because the MySQLi extension for PHP is not installed. Check your <code>PHP.ini</code> to see how you can enable it.</p>
<p>For more help, see the <a href="http://drupal.org/node/258">Installation and upgrading handbook</a>. If you are unsure what these terms mean you should probably contact your hosting provider.</p>');
    exit;
  }

  $url = parse_url($url);

  // Decode url-encoded information in the db connection string
  $url['user'] = urldecode($url['user']);
  // Test if database url has a password.
  if(isset($url['pass'])) {
    $url['pass'] = urldecode($url['pass']);
  }
  else {
    $url['pass'] = '';
  }
  $url['host'] = urldecode($url['host']);
  $url['path'] = urldecode($url['path']);
  if (!isset($url['port'])) {
    $url['port'] = NULL;
  }

  $connection = mysqli_init();
  @mysqli_real_connect($connection, $url['host'], $url['user'], $url['pass'], substr($url['path'], 1), $url['port'], NULL, MYSQLI_CLIENT_FOUND_ROWS);

  // Find all database connection errors and error 1045 for access denied for user account
  if (mysqli_connect_errno() >= 2000 || mysqli_connect_errno() == 1045) {
    drupal_maintenance_theme();
    drupal_set_header('HTTP/1.1 503 Service Unavailable');
    drupal_set_title('Unable to connect to database server');
    print theme('maintenance_page', '<p>If you still have to install Drupal, proceed to the <a href="'. base_path() .'install.php">installation page</a>.</p>
<p>If you have already finished installing Drupal, this either means that the username and password information in your <code>settings.php</code> file is incorrect or that we can\'t connect to the MySQL database server. This could mean your hosting provider\'s database server is down.</p>
<p>The MySQL error was: '. theme('placeholder', mysqli_connect_error($connection)) .'.</p>
<p>Currently, the username is '. theme('placeholder', $url['user']) .' and the database server is '. theme('placeholder', $url['host']) .'.</p>
<ul>
  <li>Are you sure you have the correct username and password?</li>
  <li>Are you sure that you have typed the correct hostname?</li>
  <li>Are you sure that the database server is running?</li>
  <li>Are you sure that the mysqli libraries are compiled in your PHP installation? Try using the mysql library instead by editing your <code>settings.php</code> configuration file in Drupal.</li>
</ul>
<p>For more help, see the <a href="http://drupal.org/node/258">Installation and upgrading handbook</a>. If you are unsure what these terms mean you should probably contact your hosting provider.</p>');
    exit;
  }
  else if (mysqli_connect_errno() > 0) {
    drupal_maintenance_theme();
    drupal_set_header('HTTP/1.1 503 Service Unavailable');
    drupal_set_title('Unable to select database');
    print theme('maintenance_page', '<p>We were able to connect to the MySQL database server (which means your username and password are okay) but not able to select the database.</p>
<p>The MySQL error was: '. theme('placeholder', mysqli_connect_error($connection)) .'.</p>
<p>Currently, the database is '. theme('placeholder', substr($url['path'], 1)) .'. The username is '. theme('placeholder', $url['user']) .' and the database server is '. theme('placeholder', $url['host']) .'.</p>
<ul>
  <li>Are you sure you have the correct database name?</li>
  <li>Are you sure the database exists?</li>
  <li>Are you sure the username has permission to access the database?</li>
</ul>
<p>For more help, see the <a href="http://drupal.org/node/258">Installation and upgrading handbook</a>. If you are unsure what these terms mean you should probably contact your hosting provider.</p>');
    exit;
  }

  /* Force UTF-8 */
  mysqli_query($connection, 'SET NAMES "utf8"');

  return $connection;
}