Recommend a browser/server n-tier architecture because renters are likely to be familiar with using a browser. Also, the DBMS and application could be split across servers to improve efficiency.
Each car needs a smart card reader and GPS. The smart card reader is to authorize the renter's use of the car by reading that person's identifying smart card and matching it against the rental assignment on the DBMS. A GPS is required to keep track of cars so that a renter can find the nearest car that is available for rental.
The smart card needs to store a unique encrypted code to identify the renter.
A possible alternative to the smart card is a cell phone. GSM phones contain a SIM card that uniquely identifies the phone (and thus the owner). The phone owner could dial the car to unlock it. A SIM is a smart card.
A company supplies pharmaceuticals to sheep and cattle stations in outback Australia. Its agents often visit remote areas and are usually out of reach of a mobile phone network. To correctly advise station owners and take orders, the agents are equipped with a PDA. What data management strategy would you recommend for the company?
The company will need to use replication. Before an agent moves out of mobile phone range, the agent needs to synchronize his/her PDA. While in the outback, the agent can access data on the PDA, update records, and so forth. When the agent is next within range of a mobile phone network, he or she can synchronize again.
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This page is part of the promotional and support material for Data Management (fifth edition) by Richard T. Watson |