zend_db: grasping basic concepts

Bootle · #1 (**permalink**) 10-01-2007, 11:05 PM

Just started on the zend framework, and was wondering if every model that requires database access has to extend zend_db_table_row? For instance, if i have an author class, i assume the author finder/ gateway extends zend_db_table? This means that the returned/ found author must extend zend_db_table_row, is that correct? What if the author model contains a collection of books by that author - how is that relationship expressed in terms of zend_db_table and zend_db_table_row? Is it considered good mvc practice to pass models to the view that have a db-accessable interface, or should they be "read-only" objects? Would you always use the zend_db_* interface for db access, or would you ever use pdo directly in a model?

Thanks for any answers, i hope someone can clear this confusion for me

Elemental · #2 (**permalink**) 10-05-2007, 01:19 AM

I'm not sure I completely follow your questions, but here's I deal with it all...

For a database connection I will reuse often or need to access more than just a couple of tables in I create and register an adapter via Zend_Db::factory();

Code:

Zend_registry::set('dbDefault',
                   Zend_Db::factory('Pdo_Mysql', array(
                                    'host'     => '127.0.0.1',
                                    'username' => 'webuser',
                                    'password' => 'xxxxxxxx',
                                    'dbname'   => 'test'
                  )));

then I create a model by extending Zend_Db_Table

Code:

class Bugs extends Zend_Db_Table_Abstract
{
    protected $_name = 'bugs';
}

If that table is in my default adapters db its straight forward

Code:

$table = new Bugs();

If that table is in another adapter:

Code:


$db = Zend_Registry::get('myDbAdapter');
$table = new Bugs(array('db' => $db));

now you have a table object and you can run your queries via the docs...
since its a Zend_Db_Table type object the results will be of type Zend_Db_Table_Rowset.

The rowset can be turned into an array and you can mold it to your needs then feed the array to the view, etc.

Bootle · #3 (**permalink**) 10-05-2007, 11:41 AM

Thanks for the reply.

How likely are you to have more than one adapter in a project? It seems the only viable use would be for different adapters to point to different databases?

With regards to my original post, i'll try and explain it a little better.

Whereas i'm currently used to creating a model, say Author, and using pdo from within the class to populate it's properties (activerecord i suppose?), after reading the docs on zend_db_table it seems that for any model in the application that requires db access, i need to make it a child of zend_db_table_row, since the gateway returns an object of that type.

eg:

PHP Code:


			
class Author
{
   function load($id){
      $record = $this->db->prepare('select * from authors where id=?', $id)->fetchRow();
      $this->name = $record['forename'] . ' ' . $record['surname'];
      $this->id = $record['id'];
      //etc
}

See, it's like i used to build the objects following the activerecord approach? Well that way, an author is an author. Now if i use the zf approach, it would be something like:

PHP Code:


			
class Author extends zend_db_table_row
{}

is that right? Meaning that the author interface now has a load of data access methods?

Elemental · #4 (**permalink**) 10-05-2007, 02:47 PM

I see what your saying now I think:

Code:

class Authors extends Zend_Db_Table_Abstract {
  //table definition
}

class Author extends Zend_Db_Table_Row {
  //individual record from Authors table
}

I guess there's nothing wrong with that, but it would only really be necessary if you need to alter to default behavior of Zend_Db_Table_Row. Anything you pull out of a Zend_Db_Table object will be of type Zend_Db_Table_Row or Rowset. If you query straight off the db adapter you'll get arrays mostly.

I currently have a project underway that connects to no less than 6 different dbs on 4 diferent servers, and we're just dealing with infrastructure at the moment, no real function pages have been producted... so yes is very possible within the enterprise to have a set of db adapters as apposed to a single adapter.

Elemental · #5 (**permalink**) 10-08-2007, 04:47 PM

Here's a free webinar I found that might help, I know I plan on checking it out!

Events / Company / Zend.com

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