num_rows not work on object

[eluser]RJ[/eluser]
This is an ODBC query, the value of $query is:

CI_DB_odbc_result Object ( [conn_id] => Resource id #123 [result_id] => Resource id #124 [result_array] => Array ( ) [result_object] => Array ( ) [current_row] => 0 [num_rows] => -1 [row_data] => )

The query being ran is:

Code:

SELECT devicetype, subversion
FROM (ttdevice)
WHERE msisdn = ‘xxxx'
AND unitid = ‘xxxx’

I can get the data out now running the foreach without num_row check; num_row doesn't recognize the result above as a row thereby returning value of -1. There has to be a different check or maybe pull the data out as an array and check?