/**
* Connects to the sql database and runs a sql query.
*
* @param sql_query $sql mysql query to be performed on the database.
* @return object|boolean returns a mysqli_result object if data is retrieved from the database
* or boolean value if there is no data(true on success/false on failure).
*/
protected static final function query($sql)
{
if (self::$conn == null) {
self::$conn = new mysqli(self::$servername, self::$username, self::$password, self::$dbname);
if (self::$conn->connect_error) {
die("Connection failed: " . self::$conn->connect_error);
}
}
return self::$conn->query($sql);
}
