将会话userdata插入CodeIgniter中的新数据库

How would I go about inserting the session userdate id into my new table using the form I have in my view so that I may use the id as a foreign key?

Controller:

function validate_credentials() {
    $this->load->model('member_model');
    $query = $this->member_model->validate();
    if ($query) { // if user credentials validate the user session start
        $data = array(
            'username' => $query->username,
            'id' => $query->id,
            'first_name'=>$query->first_name,
            'is_logged_in' => true
        );

        $this->session->set_userdata($data);

        redirect('members/members_area');
    } else {
        $this->index();
        echo 'Incorrect Password or Username';
    }
}

View:

echo form_open('banks/create_bank');
echo form_input('bank_name', set_value('bank_name', 'Account Name'));
echo form_input('interest', set_value('interest', 'Interest'));
echo form_input('start_amount', set_value('start_amount', 'Starting Balance'));
echo form_input('length', set_value('length', 'Length'));
echo form_submit('submit', 'Create Account')
echo validation_errors('<p class="error"/>'); 

Try this :

echo form_open('banks/create_bank');
echo form_input('bank_name', set_value('bank_name', 'Account Name'));
echo form_input('interest', set_value('interest', 'Interest'));
echo form_input('start_amount', set_value('start_amount', 'Starting Balance'));  
echo form_input('length', set_value('length', 'Length'));

**echo form_input('id', set_value('id', $this->session->userdata('id'));**

echo form_submit('submit', 'Create Account')
echo validation_errors('<p class="error"/>'); 

Note : where 'id' in first parameter of form_input function can be replace by any name you want to pass when form will be submit.

In the method used in the controller banks where you handle the posted data from the from.

add something like this:

$data = array('bank_name' => $this->input->post('bank_name'), // add more post data

              'id' => $this->session->userdata('id') ); //this will take the 
                                                 //value 'id' from session

and pass it to your respective model.