仅在需要时自动连接到 PDO

I don't want to open PDO connections by default to all three database as its a waste of resources and will slow the execution time down. So my thought is to wrap all SQL queries within a function. The first time that a query is executed on a non-open PDO connection, the try {} error handler can catch it, find out what the problem was (in this case connection doesnt exist), then open the connection and re-execute the query. That way, the database is only being connected to as and when needed - as long as the connection string (host, database, username, password) are all defined in advance, I can't see any problem in it working.

但是，我需要继续推进，并且在大约 7 天内无法访问开发箱，所以任何人都可以看出这种情况有什么问题吗?另外，如果没有打开连接，谁能告诉我 handler->errorInfo() 将返回的错误消息?

class Wrapper {
    private static $db;

    public static function someQuery() {
        $db = self::getDatabase();
        // now go on to execute the query
    }

    private static function getDatabase() {
        if (self::$db === null) {
            self::$db = // connect here
        }
        return self::$db;
    }
}