Why Can't My CodeIgniter App Connect to My MySQLi Database?

CodeIgniter: Troubleshooting "Unable to Connect to Database Server" Error with MySQLi

When switching from the MySQL to MySQLi driver in CodeIgniter, encountering the error:

Unable to connect to your database server using the provided settings.

can be particularly frustrating. This error indicates a problem with the database connection settings you have configured.

To resolve this issue, first inspect your database configuration settings. Ensure that the following are correct:

• Hostname: Verify that the hostname is correct. If you are connecting to a local database, use localhost.
• Username: Check the username for any typos or incorrect case.
• Password: Confirm that the password is accurate and matches the password for the specified database user.
• Database: Make sure the database name is correct.
• DBDriver: Ensure that the dbdriver is set to mysqli.
• Port: If your MySQL server is using a non-default port, specify it using the port configuration option.

After verifying these settings, it is recommended to debug the database connection by adding the following code to the end of the database.php configuration file:

echo '<pre class="brush:php;toolbar:false">';
print_r($db['default']);
echo '

'; echo 'Connecting to database: ' .$db['default']['database']; $dbh=mysql_connect ( $db['default']['hostname'], $db['default']['username'], $db['default']['password']) or die('Cannot connect to the database because: ' . mysql_error()); mysql_select_db ($db['default']['database']); echo '
'; echo 'Connected OK:' ; die( 'file: ' .__FILE__ . ' Line: ' .__LINE__);

This code will display the connection settings and attempt to connect to the database. If there is an error during connection, it will provide a detailed error message that can help identify the root cause.

By following these steps and carefully debugging the connection settings, you should be able to resolve the "Unable to Connect to Database Server" error and establish a successful connection to your database using MySQLi in CodeIgniter.

The above is the detailed content of Why Can't My CodeIgniter App Connect to My MySQLi Database?. For more information, please follow other related articles on the PHP Chinese website!