Reference to undefined property $.hdb - s9hanaxs

I am using this code to call store procedure but when I execute .xsjs I get this error:

Found the following errors:

===========================

ReferenceError: reference to undefined property $.hdb (line 5 position 0 in /s0015145715trial/development/machines/services/MachinesJSON.xsjs)

Code:

5.     var conn = $.hdb.getConnection();
6.     var getResult = conn.loadProcedure("_SYS_BIC", "s0015145715trial.development.machines.data.storeProcedure::machines");
7.     var result = getResult("param1","param2");

8

9.      $.response.contentType = "application/json";
10.     $.response.status  = $.net.http.OK;
11.     $.response.setBody(JSON.stringify(result));
12.     $.response.headers.set('access-control-allow-origin','*');