How to collect the field vlaues.

this is a simple example to store data to a custom db:-

public function validation_{page_slug}( $aInput, $aOldInput ) {
global $wpdb;
if(isset( $aInput[“submit_button_id”]))
{
$updated= $wpdb->update( ‘wp_test’, array(‘data’=>$aInput[‘test_data’]),array(‘id’=>$_GET[‘id’]));

if($updated)
{
$this->setSettingNotice( ‘your message here’, ‘updated’,
$this->oProps->strOptionKey, true );
return array(‘n/a’);

}
}