php - Zend_Validate_Db_RecordExists or empty value -

i've got (hopefuly) simple task, , google fu has failed me. basically, i've got form select contains empty value , number of ids given content can belong to. want - validate if given ids exist, if value set. this:

$field = new zend_form_element_select('field'); $field->addvalidator(     new zend_validate_db_recordexists(         array(             'table' => 'categories',             'field' => 'id'         ) )); 

takes care of checking if given id exists, i'm not able find way omit if value empty. 1 way move logic isvalid method, i'm hoping there's nicer way accomplish task.

try set form element not required:

$field->setrequired(false); 

when element not required , not filled, validators queue won't run.

quick example works me:

// zend_form form body $this->addelement('select', 'category', array(         'label' => 'choose category',         'required' => false,         'multioptions' => array(                 null => 'no category selected',                 '1' => 'one',                 '2' => 'two',            ),         'validators' => array(                 array('db_norecordexists', false, array(                         'schema' => 'public',                         'table' => 'category',                         'field' => 'id',                     )),          ), ));