Database exists but returns an error saying “Unknown Database”
问题 I installed WAMP server few hours ago into my Windows 10 64-bit computer. I used phymyadmin to create a database named ' testdb ' and tried to connect to it with a php file. I am sure that I created the database, but it returns this error: "Warning: mysqli_connect(): (HY000/1049): Unknown database 'testdb' in C:\wamp64\www\projects\index.php on line 7" Here is the php file. <?php define('DB_SERVER', 'localhost'); define('DB_USERNAME', 'root'); define('DB_PASSWORD', ''); define('DB_NAME',