资 源 简 介
This class extends the PDO object to provide DB abstraction - a simple way to query different types of databases without needing to change your code.
PDO:
PDO provides a data-access abstraction layer, which means that, regardless of which database you"re using, you use the same functions to issue queries and fetch data. PDO does not provide a database abstraction; it doesn"t rewrite SQL or emulate missing features. You should use a full-blown abstraction layer if you need that facility. - http://php.net/manual/en/intro.pdo.php
However PDO does not cover DB query-abstraction - for that you have to use some huge class like ADOdb or PEAR:DB. Which of course will slow your site to a crawl if you are using shared hosting.
This class fills this gap and provides DB query-abstraction for common
