Is_Unique validation with custom db table

[eluser]wehappyfew[/eluser]
Hello to all,

i am trying to create a custom table for every user that is creating an account in my site.
For example:

Code:

function add_client($form_inputs)
{
  //create the table name
  $username = $this->session->userdata('username');
  $table_name = $username . "_clients";
  //
  $this->db->insert($table_name,$form_inputs);
}

The above works fine.
BUT...i would like something more.
I would like a form validation to check for unique values in the custom table.

for example:

Code:

$field_rules =array
               (
                     'field'   => 'client_name',
                     'label'   => '-Client\'s name-',
                     'rules'   =>
required|
max_length[30]|
----------------> is_unique[{$username}_clients.client_name]|
alpha_dash|trim'
               )

The thing is that i dont know how to "integrate" the username variable into the validation.
Thank you in advance!


Oh..i though of something else that may be a solution.
It would be the same if i could create a table from the DBFORGE class ( create_table() ) where i could set the colunm index as UNIQUE.
But it seems that is not possible to set the column index anyway.