|''begin transaction for client''| Joanna |''staff''| Bill|
|''book''|2||coffee dispenser|''on''|2004/05/08 09:01|''for''|2 hours|
|''pay with cash $''|6.00|
|''complete transaction''|
 * ''Checks''
|''client booking list''|Joanna|
|''rental item''|''count''|''start date''|''end date''|
|coffee dispenser|2|2004/05/08 09:01|2004/05/08 11:01|

|''rental item subset''|
|''name''|''free count''|
|coffee dispenser|10|