Call to a member function on non object in CodeIgniter - sql

Question

I'm trying to validate an username and check if this already exists in the system. Now the problem's that I've the user list in the table: ea_user
and the user settings in the table: ea_user_settings. Now:
ea_user > contain the id of the user that isn't remove from the system, the field 'data'
ea_user_settings > contain the username
So my function is this:
public function validate_username($username, $user_id)
{
$num_rows = $this->db->join('ea_user_settings', 'ea_user_settings.id = ea_user.id', 'inner')
->get_where('ea_user_settings',
array('username' => $username, 'id_users <> ' => $user_id, 'ea_user.data' => 0))->num_rows();
return ($num_rows > 0) ? FALSE : TRUE;
}
The problem's I get this error:
Fatal error: Call to a member function num_rows() on a non-object

Answer 1

Try this
public function validate_username($username, $user_id)
{
$this->db->select(*);
$this->db->from('table_name');
$this->db->join('ea_user_settings', 'ea_user_settings.id = ea_user.id', 'inner')
$this->db->get_where('ea_user_settings', array('username' => $username, 'id_users <> ' => $user_id, 'ea_user.data' => 0));
$query = $this->db->get();
$result = $query->result_array(); # add this
$count = count($result);
if (!empty($count)) {
return true;
}
else{
return false;
}
}
}

Answer 2

It isn't documented, but any of the get() functions (get_where() in your case) can return FALSE. (Learned this the hard way.) That would seem to be your problem. FALSE->num_rows() has no meaning as FALSE is not a object.
This usually happens because the query does not build correctly.
The compiled query can be examined by doing this.
public function validate_username($username, $user_id)
{
$this->db->select(*)
->from('ea_user_settings')
->join('ea_user_settings', 'ea_user_settings.id = ea_user.id', 'inner')
->where(array('username' => $username, 'id_users <> ' => $user_id, 'ea_user.data' => 0));
$compiled_select = $this->db->get_compiled_select(NULL, FALSE);
//inspect or var_dump($compiled_select) to see what query statement was built.
After setting up all the join, where and other pieces of a query I have taken to checking the truthiness of get() before using its return. In your case something like this. Code picks up after (or instead of) the line $compiled_select = $this->...
if($query = $this->db->get())
{
return ($query->num_rows() > 0) ? FALSE : TRUE;
}
else
{
throw new Exception("get call returned FALSE");
}
}
For me, the Exception is useful mostly during development. But you could put your call to the validate_username() in a try catch block if it would be useful.