Transform Map Script

[aagman4]

Control table extends table - Control/Risk. Transform map is on Control/Risk table. I wanted to update custom fields u_key_entity and u_key_system present in Control table. I am using below code in Transform Script but it is being ignored with error - Invalid map target u_key_system does not exist in table sn_compliance_control

if (source.u_class == 'Control') {

        var controlInfo = new GlideRecord('sn_compliance_control');

        controlInfo.addQuery('number', source.u_number);

        controlInfo.query();

        if (controlInfo.next()) {

            controlInfo.u_key_entity = source.u_internal;

            controlInfo.u_key_system = source.u_other;

        }

    }

Let me know if I am missing anything here.

Thanks in advance!