how to insert zend form values in two tables in zend?

i have two tables users and userslog where i have users contains id, username,email,gender and userslog contains id,firstname,lastname,designation and u_id which is foreign key of users table.

my register controller

class RegisterController extends Zend_Controller_Action
{

public function init()
{
    /* Initialize action controller here */
}

public function indexAction()
{

    $form = new Application_Form_register();
    $this->view->form = $form;

    if($this->getRequest()->isPost())
    {
        $data = $this->getRequest()->getPost();
    }


}


}

my register model is

 class Application_Model_DBtable_register extends Zend_Db_Table
{
protected $_name = 'users';
// i have to define two tables here!! how?
}

my register zend form

class Application_Form_register extends Zend_Form
{
public function init()
{
    $this->setName('register');
    $this->setMethod('post');

    $firstname = $this->createElement('text', 'firstname');
    $firstname->setLabel('FirstName: ')
                ->setRequired(true)
                ->setFilters(array(
                        'stringTrim','StringToLower'));

    $lastname = $this->createElement('text', 'lastname');
    $lastname->setLabel('LastName: ')
            ->setRequired(true)
            ->setFilters(array(
                    'stringTrim','StringToLower'));

    $email = $this->createElement('text', 'email');
    $email->setLabel('Email: ')
            ->setRequired(true);

    $username = $this->createElement('text', 'username');
    $username->setLabel('UserName: ')
            ->setRequired(true)
            ->setFilters(array(
                    'stringTrim','StringToLower'));

    $password = $this->createElement('password', 'password');
    $password->setLabel('Password: ')
            ->setRequired(true);

    $password2 = $this->createElement('password', 'password2');
    $password2->setLabel('Confirm Password: ')
            ->setRequired(true);

    $submit = $this->createElement('submit', 'register');
    $submit->setLabel('Register')
            ->setIgnore(true);

    $this->addElements(array(
            $firstname,
            $lastname,
            $email,
            $username,
            $password,
            $password2,
            $submit));
}

}

how can i do it? can we use Zend_Auth for authentication? if yes then how.please give me example. I saw $_dependantTable and $_referenceMaps but i can't undestand it . I am confused how to do it because i am not able to define table name more than once in a class. i have to insert the values at same time in two different tables.

ok this is incorrect:

class Application_Model_DBtable_register extends Zend_Db_Table
{
protected $_name = 'users';
// i have to define two tables here!! how?
}

The intent of classes that have DbTable in their names is that they they are the adapter/gateway to a single database table.

So your issue would breakdown into at least 2 classes/files:

class Application_Model_DBtable_Users extends Zend_Db_Table
{
protected $_name = 'users';
}

class Application_Model_DBtable_Userslog extends Zend_Db_Table
{
protected $_name = 'userslog';
}

I would at this level put a method in either class that does the actions required to register a user. Later you may decide to use mappers and domain objects.

class Application_Model_DBtable_Users extends Zend_Db_Table
{
    protected $_name = 'users';
    /*
     * psuedocode not meant for production
     */
    public function register($array $data) {
        //sort out the data
        $user = array();//put the elements from the $data array that you want to go into the users table
        $userLog = array(); //same thing for the userslog table
        //get userslog adapter
        $userlogTable = new Application_Model_DbTable_Userslog();
        //do the first insert         
        $result = $this->insert($user);
        //insert returns the primary key of the row created,
        $u_id = array('u_id' => $result);
        $userLog = array_merge($u_id, $userLog); //merge u_id with existing data
        //perform second insert
        $result2 = $userlogTable->insert($userLog);
        //handle any errors
    }
}

This should provide a basic example to demonstrate the steps you might take to implement you design. The point behind the DbTable models is to abstract the connection to a given table, each table has it's own DbTable model. The DbTable model provides an adapter to each table and access to the api provided by Zend_Db_Table_Abstract.

The Steps shown above could just as easily be taken in a third model or in the controller itself.

Note: There may be away to do this with one sql statement but I'm not the person who knows that answer.