db_connect
- drupal
| Versions | |
|---|---|
| 4.7 – 6 | db_connect($url) |
Initialize a database connection.
Note that you can change the mysql_connect() call to mysql_pconnect() if you want to use persistent connections. This is not recommended on shared hosts, and might require additional database/webserver tuning. It can increase performance, however, when the overhead to connect to your database is high (e.g. your database and web server live on different machines).
Related topics
Code
includes/
<?php
function db_connect($url) {
$url = parse_url($url);
// Check if MySQL support is present in PHP
if (!function_exists('mysql_connect')) {
// Redirect to installer if using default DB credentials
if ($url['user'] == 'username' && $url['pass'] == 'password') {
include_once 'includes/install.inc';
install_goto('install.php');
}
drupal_maintenance_theme();
drupal_set_header('HTTP/1.1 503 Service Unavailable');
drupal_set_title('PHP MySQL support not enabled');
print theme('maintenance_page', '<p>We were unable to use the MySQL database because the MySQL 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;
}
// 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']);
// Allow for non-standard MySQL port.
if (isset($url['port'])) {
$url['host'] = $url['host'] . ':' . $url['port'];
}
// - TRUE makes mysql_connect() always open a new link, even if
// mysql_connect() was called before with the same parameters.
// This is important if you are using two databases on the same
// server.
// - 2 means CLIENT_FOUND_ROWS: return the number of found
// (matched) rows, not the number of affected rows.
$connection = @mysql_connect($url['host'], $url['user'], $url['pass'], TRUE, 2);
if (!$connection) {
// Redirect to installer if using default DB credentials
if ($url['user'] == 'username' && $url['pass'] == 'password') {
include_once 'includes/install.inc';
install_goto('install.php');
}
// Show error screen otherwise
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', mysql_error()) . '.</p>
<p>Currently, the username is ' . theme('placeholder', $url['user']) . ' and the database server is ' . theme('placeholder', $url['host']) . '.</p>
<ul>
<li>Are you sure you have the correct username and password?</li>
<li>Are you sure that you have typed the correct hostname?</li>
<li>Are you sure that the database server is running?</li>
</ul>
<p>For more help, see the <a href="http://drupal.org/node/258">Installation and upgrading handbook</a>. If you are unsure what these terms mean you should probably contact your hosting provider.</p>');
exit;
}
if (!mysql_select_db(substr($url['path'], 1))) {
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', mysql_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;
}
/* On MySQL 4.1 and later, force UTF-8 */
if (version_compare(mysql_get_server_info(), '4.1.0', '>=')) {
mysql_query('SET NAMES "utf8"', $connection);
}
return $connection;
}
?>It's full of delicious functions!
