Originally posted by yc
Wouldn't that mean that each computer would be equal to stay one product in a supermarket, then none of the data there would redundant?
I don't understand your question
Originally posted by yc
I can understand normalising that table into two tables so that the computer info is seperate to its location etc, but where was the redundancy?
The redundancy lies in the fact that you had the same barcode, entered a gazillion times into one (or more) tables. The data had been superfluous, unwanted, unneeded, unnecessary. You are getting confused with your "computer info is seprate from its location". I am talking about having the central database, containing redundant data by having the same,
existing data duplicated time and time again over the same fields, in the database itself (could be flat database, could be a relational database).
I am looking at Q21(b), 2002 IPT HSC.
Identify data redundancy in Mr Ferranos database and outline the problems it may cause as the database increases in size..
Data redundancy via:
* Computer ram in duplicate cells
First example, "64" in computer RAM, copied over twice.
Second example, "8" under computer hard disk, copied twice.
Obvious data redundancy:
Location, "Manager's Office" and "Reception" are entered twice in each case, when only one was required in each location, either "Reception" or "Manager's Office", not twice over, and twice again (for each location).
Phone extension duplicates,
You will see "3227" and "1859" occurring twice, when this is not necessary with normalisation and creating a relational database (introducing foreign keys).
Lastly, "Room Number"
ie "9023" is repeated twice, "9115" is also repeated twice.
The question asks you to identify,
That'd be worth about 1 or even 2 marks tops.
I've done that,
identifying the redundant data.
Second part of the question,
outline the problems it may cause as the database increases in size.
You could talk about loading times, processing times, search times, indexing times, backup times, backup schedules, delays in processing, sorting, searching, saving data, editing data, deleting records, blah blah.
Whatever you do to it, whether it be:
adding, deleting, editing, sorting, searching, processing, opening, sending, saving, whatever! it will be exponentially increasing as you shove more and more
redundant data into the existing database.
You have "005" computers now, but what if this happened in a company with five hundred thousand computers? (500,000). Think about the data redundancy there. In the question, we have seen a fair few fields which contain redundant data, now think about this: our data has been duplicated twice, for five computers. How many fields would be duplicated (ie making data redundant/useless) if we had 500,000 computers, instead of 5?
That will get you the 3 marks.
Onto your second question, Q22(b)
Outline the advantages for Jill of using mobile technology to undertake her work.
Here, you would talk about your communication systems and transmission medium.
The question gives you a diagram,
use it.
Answer all of part (a), then move onto (b) - the question,
in question
Now, using mobile technology such as:
* mobile phones
* satellite
* wireless transmission
* microwave
* wireless LAN
The question is not asking "why is she using a laptop, instead of a desktop computer", it is asking (let me say it again): "
Outline the advantages for Jill of using mobile technology to undertake her work."
Therefore, you would need to talk about the aforementioned mode of transmission.
The advantages? let's run through them now.
* moves data through air and space, doesn't require cabling
* does not need a fixed location
* signals can be bounced through space, off towers, receivers, ground stations, etc
* covers long distances
* faster than telephone lines and coaxial cables (compare the wireless transmission medium that Jill uses with physical wired transmission)
* error free transmission
* can send large amounts of data over long distances
* portable
* Jill doesnt have to stay put, in one fixed location
now, that will probably get you 2 marks out of the 3.
2 marks for identifying a few advantages (see above dot points)
and for the bonus (third) mark, you
must relate the advantages (aforementioned) to the scenario in question.
So, for the final 1 mark, you might like to say things like:
* since Jill is a sales representative, selling wine throughout the state, she needs to be mobile all the time and cannot afford to stay in the one location (half a mark here)
* jill logs onto her work network daily to send and receive data, this requires her to download and transfer at much faster speeds than ordinary phone lines will offer
* as she visits customers, she can transmit data at reasonably error free rates through air and space, therefore she doesn't require the physical fixed location of a phone line or coaxial connection
* as she travels across the state and visits customers, she can cover long distances whilst still knowing that she can transmit and receive data from her workplace via high transmission mediums such as satellite and microwave (in comparison to copper telephone lines)
* microwave transmission is faster, mobile phones are faster than 'dialling' into her workplace using a normal telephone and having to transfer/connect calls, talk to secrateries, go through people, etc.
* the portability of mobile computing and the use of mobile technology allows jill to work wherever she pleases, visiting customers from one suburb to another, while maintaining strong links with her workplace daily through the transmission/reception of data via microwave and satellite (wireless) transmission media.
* large amounts of data can be sent (this is the biggie) in comparison to existing telephone lines/networks
hope that answers your question yc.
ps, about your textbook re-writing... i can do that
i need to do some
real work now, lol...
