Exectue a prepared statement consisting of $query interposed with $params. Results will then become a property of the database object accesible by InvDB::fetch() and InvDB::fetchAll().
$query (STRING) - a complete database query string, with placeholders for parameters
$params (ARRAY) - an array of values to be replaced into the prepared statement
BOOL
$this->obj_db->prepareAndDoQuery('SELECT * FROM `document` WHERE `document_title` = ? AND `document_node` = ?' , array('Home' , 2));