10.5 Asynchronous Usage Example

As you will discover, the asynchronous mechanism can be used in many powerful ways. At this point, however, let's look at a very simple example just to see how it works.

int
main() {
  RWDBDatabase aDb = RWDBManager::database(
                                "SYBASE_CT",
                                "sybase_server",
                                "sybase_user",
                                "password",
                                "DEMO_DB"
                       );

  RWDBConnection asyncConn =
       aDb.connection(RWDBConnection::Asynchronous);           //1
  RWDBResult result = 
       aSyncConn.executeSql("create table X(y int)");          //2
  while (! result.isReady()){                                  //3
    // Do something useful here 
    cout << "Waiting for completion " << endl;                 //4
  }

  assert(result.isValid());                                    //5
  return 0;
}

On //1 an asynchronous connection is obtained from the database object. On //2 a create table query runs using the ::executeSql method. This method has been invoked asynchronously by supplying the asynchronous connection obtained in //1. Then //3 checks whether the returned RWDBResult object is ready or not. If the RWDBResult object is not ready, it goes into the loop and does some work in //4. In this example, the work done in //4 gets repeated until the RWDBResult object gets to a ready status. //5 checks whether the call has been executed correctly or not.