Zend_DB_Select Woes
It's no secret, I'm a fan of the Zend Framework, which I've been using since version 0.15. A lot of components have been added since then, and many of the initial components have been refactored and enhanced, and have matured. And that includes the Zend_Db_Select component, which has been evolving quite nicely, and even Zend_Db_Table_Abstract based classes make use of Zend_Db_Table_Select, which extends Zend_Db_Select.
But ultimately, there's still something lacking: Support for vendor specific SQL extensions, such as MySQL's SQL_CALC_FOUND_ROWS. Generally speaking, keeping Zend_Db_Select ANSI SQL compliant is a Good Thing™, as it forces (mostly) standards compliant queries (with the exception of the LIMIT clause, which invokes the database adapter to generate the SQL snippet), which may help with portability. Still, full support for features offered would be nice, and often is the reason why a particular database was chosen to begin with (among other reasons such as performance, budget, corporate policy, developer experience, etc).
Up until now I've always patched my local copy of the Zend/Db/Select.php file with support for that particular extension. That way I could call $select->calcFoundRows(true)->from([..]); and not have to give up using Zend_Db_Select. Of course doing it this way is not exactly best practice — a vendor specific extension shouldn't be implemented like that in a more universal component. For my purposes that's fine, since I just work with MySQL and SQLite, but ultimately there needs to be better support for these extensions.
A cleaner way to implement the extra functionality is to extend Zend_Db_Select, and add the extension support there. With ZF 1.6 RC1 that means overwriting the protected static $_partsInit, and adding the correlating _render*() method that gets called in Zend_Db_Select::assemble().
There are discussions about this on the Zend Framework mailing list, and they provide interim solutions. It's especially useful in conjunction with the proposed Zend_Paginator, which is part of ZF 1.6 RC1.
However, getting a select object with $dbAdapter->select(); is still an issue. Instead, one would have to manually call $select = new My_Db_Select($dbAdapter);, and that's something I'd like to avoid. It would also trigger a chain reaction and require one to extend Zend_Db_Table_Abstract with My_Db_Table_Abstract, which calls My_Db_Table_Select instead of Zend_Db_Table_Select, which in return extends My_Db_Select instead of Zend_Db_Select. Not pretty. And it's definitely a good example of why I, like many other OO developers, favor "composition over inheritance."
I'd almost like to see PHP getting proper support for mixins. I could see Zend_Db_Select emulating mixins or supporting plugins by registering plugin classes and using __call() to iterate over those classes to add functionality to the core, which the individual database adapters then register — something like Zend_Db_Select_Plugin_Mysql.php, but honestly, that seems a bit overkill, and a tad bit too unclean for my taste, but perhaps that's the way to go. It's how Doctrine implements Table plugins, and who knows, maybe it paves the road to what could one day be supported natively by PHP 6.3 or 7. After all, Perl, Python, Ruby, JavaScript and many other dynamic languages support it.
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