Getting last inserted index mysql

Question

I am using ADODB to connect to my database. After I submit the query I want to get the ID of the last inserted row (from the query just inserted).

ADODB has an Insert_ID() function that should retrieve this is but it is not...
db->Insert_ID()
is not working, neither is
db->Insert_ID($table, $key)

They both just return empty values. I doubled checked my table and the insert statement is indeed working, a new row is being put in, and the key is auto_increment. Am I using the Insert_ID wrong or is there a better way to retrieve the key of the last row inserted?

Thanks

Edit: Adding code

    $result = \PSU::db->Execute( $updateSQL, $values_array );
    $id = \PSU::db->Insert_ID();
    // $id = \PSU::db->Insert_ID( $table, $key );

\PSU::db is our ADODB implementation class, taking care of things like connecting, disconnecting, etc.

Answer 1

Is it possible that you are disconnecting and reconnecting to mysql between the query and the insert_id()?

Answer 2

Try this:

$result = \PSU::db->Execute( $updateSQL, $values_array );

return \PSU::db->_connectionID->insert_id ;

_connectionID must be fixed as is.

Hope it helps!