Form Validation w/ sql + codeigniter - php

Question

I'm working on creating a callback function in codeigniter to see if a certain record exists in the database, and if it does it'd like it to return a failure.
In the controller the relevent code is:
function firstname_check($str)
{
if($this->home_model->find_username($str)) return false;
true;
}
Then in the model I check the database using the find_username() function.
function find_username($str)
{
if($this->db->get_where('MasterDB', array('firstname' => $str)))
{
return TRUE;
}
return FALSE;
}
I've used the firstname_check function in testing and it works. I did something like
function firstname_check($str)
{
if($str == 'test') return false;
true;
}
And in that case it worked. Not really sure why my model function isn't doing what it should. And guidance would be appreciated.

Answer 1

if($this->home_model->find_username($str)) return false;
true;
Given that code snippet above, you are not returning it true. If that is your code and not a typo it should be:
if($this->home_model->find_username($str)) return false;
return true;
That should fix it, giving that you did not have a typo.
EDIT:
You could also just do this since the function returns true/false there is no need for the if statement:
function firstname_check($str)
{
return $this->home_model->find_username($str);
}

Answer 2

So the solution involved taking the query statement out of if statement, placing it into a var then counting the rows and if the rows was > 0, invalidate.
Although this is a more convoluted than I'd like.

Answer 3

I find your naming kind of confusing. Your model function is called 'find_username' but it searches for a first name. Your table name is called 'MasterDB'. This sounds more like a database name. Shouldn't it be called 'users' or something similar? I'd write it like this :
Model function :
function user_exists_with_firstname($firstname)
{
$sql = 'select count(*) as user_count
from users
where firstname=?';
$result = $this->db->query($sql, array($firstname))->result();
return ((int) $result->user_count) > 0;
}
Validation callback function :
function firstname_check($firstname)
{
return !$this->user_model->user_exists_with_firstname($firstname);
}