How to validate >1 field at a time, in a Zend sub-form? - zend-form

Question

I've created a 3 screen "wizard" using the Zend_Form_SubForm example from the online reference documentation.
The requirement I'm having trouble meeting is this:
If fields 1, 2, & 3 of the first screen are already in the database, notify the user that they are trying to add a duplicate record. Each of those fields has their own validators. Somehow I need to add this "group validator".
So, at its most basic level, I'm trying to do:
if($field_1_not_in_db && $field_2_not_in_db && $field_3_not_in_db){
return true;//validation OK
} else {
return false;//invalid data
}
I am coming up against several issues, though:
1) Because it applies to multiple fields, I don't know which field to attach it to. Error messages appear beside the field they are attached to, so this is important... unless I can get these "multi-field validator" errors to appear at the top of the screen, which would be ideal.
2) My validator is only receiving a single value (the value of the field I attach it to, not the values of the multiple fields it is supposed to validate).
3) I provide a link to the original (non-duplicate) record in the error message, but it escapes the link, and I can't figure out how to get around that.
The setup I'm currently using (below) actually executes fine, but NewPlace validator receives $_POST['city_fk'] as $fields, instead of the desired group of posted values.
$city_fk = new Zend_Form_Element_Select('city_fk');
$cities = array();
$city_fk->setMultiOptions($cities)
->setLabel('City')
->setDescription('The city this place is in')
->setRequired(true);
$v = array(
'place_is_unique' => array(
'NewPlace',
'fields' => array('place_name','phone_number','phone_extension','street','post_code_name'),
)
);
$city_fk->addValidators($v);
$addressSubForm->addElement($city_fk);
class My_Validate_NewPlace extends Zend_Validate_Abstract
{
public function isValid($fields)
{
$result = false;
if(!$result)
{
$this->_error('sorry, this is duplicate data. see it here');
return false;
}
return true;
}
}

Answer 1

This won't help you decide which field to attach the validation to, but...
There is a thing called a "validation context" that helps.
When you create your custom validator or form IF you specify a second optional parameter ($context = null), then Zend will auto-populate this with the entire array of posted data, which you can use to incorporate other fields values into your validation. Here's a very basic example:
$city_name = new Zend_Form_Element_Text('city_name');
$place_name = new Zend_Form_Element_Text('place_name');
$place_name->addValidator('NewPlace');
class My_Validate_NewPlace extends Zend_Validate_Abstract
{
public function isValid($value, **$context = null**)
{
if(trim($value)!='' && trim($context['city_name']) != '')
{
return true;
}
return false;
}
}