Codeigniter多维数组插入数据库

Question

Hello im trying to insert a multidimensional array into mysql using codeigniter. Im having some trouble getting the values to enter correctly. Here is how the multidimensional array looks

Array ( [2] => Array ( [A] => FName 2 [B] => LName 2 [C] => PhoneNo 2 [D] => FaxNo 2 ) [3] => Array ( [A] => FName 3 [B] => LName 3 [C] => PhoneNo 3 [D] => FaxNo 3 ) [4] => Array ( [A] => FName 4 [B] => LName 4 [C] => PhoneNo 4 [D] => FaxNo 4 ) [5] => Array ( [A] => FName 5 [B] => LName 5 [C] => PhoneNo 5 [D] => FaxNo 5 ) [6] => Array ( [A] => FName 6 [B] => LName 6 [C] => PhoneNo 6 [D] => FaxNo 6 ) [7] => Array ( [A] => FName 7 [B] => LName 7 [C] => PhoneNo 7 [D] => FaxNo 7 ) [8] => Array ( [A] => FName 8 [B] => LName 8 [C] => PhoneNo 8 [D] => FaxNo 8 ) [9] => Array ( [A] => FName 9 [B] => LName 9 [C] => PhoneNo 9 [D] => FaxNo 9 ) ) 

Here is what i've tried doing

function insertfiles($arr_data)
{
    foreach ($arr_data as $value) {
        foreach($value as $key => $a){
            $data = array(
                   'Firstname' => $a,
                   'Lastname' => $a,
                   'Phone'=>$a,
                   'Fax' =>$a
                );

                $this->db->insert('test', $data); 
        }
    }
}

Im sure im messing this up horribly, it is inserting the values into the database but it's inserting them as follows

since it wont let me upload an image im providing a link to view this image online. http://psadatadesign.com/img/test-bmp.jpg

any help would be appreciated. As im trying to figure out what i have done wrong.