使用带有Zend_Db_Table的DataMapper而不是直接使用带有数据库适配器的DataMapper有什么好处？

Question

I was going through the Zend Framework quickstart tutorial, and in their demo code they use a data mapper which uses Zend_DB_Table to access the database (see: http://framework.zend.com/manual/en/learning.quickstart.create-model.html). It seems that Zend_DB_Table doesn't use prepared statements or provide a way to use transactions though. Therefore, I'm leaning towards just using a datamapper directly with a zend_db_adapter. With that in mind, can someone advise as to the situations where Zend_DB_Table would be advantageous? Appreciate your input! Cheers.

Answer 1

In general, I see Zend_Db_Table as a quick and easy way to do single-table queries.

You can surely do joins with Zend_Db_Table, but since the class is targeted towards a specific table (after all, it is intended as a Table Data Gateway implementation), all such joins always feel - to me, at least - like an unnatural graft. In that case, I always tend towards straight adapter-based queries with joins, that could include your transaction handling.

Of course, in either case, it is certainly desirable to put all of this behind a model or mapper or service layer. Then, as you change these implementation details- say, start out with a Zend_Db_Table implementation, but later realize you need to join data from a another table, so you move to adapter-based queries - none of this will affect consumers of the model/mapper/service.

Hope this helps.