php - Zend framework prepareStatementForSqlObject and execute do not work -

in zf2, want save data coming html form database. have data mapper class (simplified version):

class organizationmapper  {  protected $dbadapter;  public function __construct(     adapterinterface $dbadapter, ) {     $this->dbadapter = $dbadapter; }      public function save()     {         $action = new insert('parties');         $action->values(['created' => 'now()']);          $sql = new sql($this->dbadapter);         $stmt   = $sql->preparestatementforsqlobject($action);         $result = $stmt->execute();     } } 

the table parties has id column (int, auto_increment, primary key), , created column (timestamp).

once submit button in html form pressed, mapper's save method called. after execution of $stmt->execute(), should see new line in parties table. check db, there's nothing. problem, likely, resides in $stmt->execute() because if put \zend\debug\debug::dump($action) + die() after $stmt->execute(), page doesn't die() , shows original form. works, however, if execute raw query without preparation, this:

   $sql = 'insert parties (created) values (now());';    $this->dbadapter->query($sql, \zend\db\adapter\adapter::query_mode_execute); 

could tell what's wrong?

just in case, below result of \zend\debug\debug::dump($stmt) + die()

object(zend\db\adapter\driver\pdo\statement)#409 (9) {   ["pdo":protected] => object(pdo)#405 (0) {   }   ["profiler":protected] => null   ["driver":protected] => object(zend\db\adapter\driver\pdo\pdo)#255 (4) {     ["connection":protected] => object(zend\db\adapter\driver\pdo\connection)#256 (8) {       ["driver":protected] => *recursion*       ["resource":protected] => object(pdo)#405 (0) {       }       ["dsn":protected] => string(62) "mysql:dbname=sampledatabase;host=localhost;charset=utf8"       ["connectionparameters":protected] => array(5) {         ["driver"] => string(3) "pdo"         ["username"] => string(7) "myusername"         ["password"] => string(12) "mysecretpassword"         ["dsn"] => string(62) "mysql:dbname=sampledatabase;host=localhost;charset=utf8"         ["driver_options"] => array(3) {           [1002] => string(16) "set names 'utf8'"           [1003] => string(16) "set names 'utf8'"           [1004] => string(16) "set names 'utf8'"         }       }       ["drivername":protected] => string(5) "mysql"       ["intransaction":protected] => bool(false)       ["nestedtransactionscount":protected] => int(0)       ["profiler":protected] => null     }     ["statementprototype":protected] => object(zend\db\adapter\driver\pdo\statement)#257 (9) {       ["pdo":protected] => null       ["profiler":protected] => null       ["driver":protected] => *recursion*       ["sql":protected] => string(0) ""       ["isquery":protected] => null       ["parametercontainer":protected] => null       ["parametersbound":protected] => bool(false)       ["resource":protected] => null       ["isprepared":protected] => bool(false)     }     ["resultprototype":protected] => object(zend\db\adapter\driver\pdo\result)#258 (9) {       ["statementmode":protected] => string(7) "forward"       ["fetchmode":protected] => int(2)       ["resource":protected] => null       ["options":protected] => null       ["currentcomplete":protected] => bool(false)       ["currentdata":protected] => null       ["position":protected] => int(-1)       ["generatedvalue":protected] => null       ["rowcount":protected] => null     }     ["features":protected] => array(0) {     }   }   ["sql":protected] => string(51) "insert `parties` (`created`) values (:created)"   ["isquery":protected] => null   ["parametercontainer":protected] => object(zend\db\adapter\parametercontainer)#400 (4) {     ["data":protected] => array(1) {       ["created"] => string(5) "now()"     }     ["positions":protected] => array(1) {       [0] => string(7) "created"     }     ["errata":protected] => array(0) {     }     ["maxlength":protected] => array(0) {     }   }   ["parametersbound":protected] => bool(false)   ["resource":protected] => null   ["isprepared":protected] => bool(false) } 

you can write :

use zend\db\sql\expression;  $action->values(['created' => new expression('now()')]);