Omg! Please Help!!!! (1 Viewer)

[Cabrera1990]

Hello can someone please give me a full/detailed explanation of this question...

PLEASEEEEEE!

I will give you my notes in return and i can tell you they are OK!

Thankssss

 

[harryboyles]

a) This part of the question is about data redundancy (aka duplicate data). You need to identify one instance where this is occurring in the example. I can see two instances: 1. The item data is repeated, for example, the data about the video camera. 2. The details about the borrowers are also repeated. You then need to describe two issues that arise as a result of this data redundancy. There are a few issues, such as having conflicting data when multiple records need to be updated. (If a borrower changes faculty, then all the records related to that borrower need to be updated. if one record isn't updated, then you can't tell which record is correct and which one is incorrect) Another issue is that if you delete one record which has the only copy of the borrower's details, then you've lost those details when you weren't meaning to delete them.

b) In this question, you need to normalise (break down) the database into three tables. When answering these types of questions, it helps to look for groups of fields that share something in common. For example, in a school database, you'd have a table for students, one for teachers, and another for classes. In this instance, you can identify the three tables as being the item, the borrower, and the loan. You need to also indicate the relationships between the tables in question (e.g. linking the both the item and borrower tables to the loan table).

c) This is another question where you need to draw a diagram, rather than use a written response. There are a few key things you need to have.

• A title for the report
• Column headers detailing the fields involved.
• Records for the data in question
• A summary row or section. This could include details like how long the item has been loaned overall or who's borrowed the item the most

It hels a lot if you've worked with Microsoft Access or a similar database program because it gives you practice in identifying the components referred to in both this question and the last.

I hope this helps. feel free to PM me if you want to ask more questions, or so we can work out a deal with regards to the notes you are offering

 

[seremify007]

OMG that question was in my 2005 HSC paper wasn't it? It looks so familiar...

Anyway would like to add to above poster's excellent answers;

a) Data redundancy wastes space (i.e. lots of duplicate data still takes up precious kilobytes!) as well as posing issues when it comes to amending data (i.e. processing time to update each records will be significant and not necessarily efficient)

b) As mentioned above, if you use Access, you'll know how the diagram should look whereby it shows three tables with the field names/variables, and which ones link to which other ones from the other tables. Refer to http://www.wulfila.be/archive/2006/DB/dictionary/Relations.png for an example. Trying to answer this question using words/sentences is pointless since it'll probably confuse both you and the marker.

c) I agree whereby drawing up a mock report and giving examples on what this shows will make it great, but it's also worth doing commentary and notes (as the question asks) to show the 'key features' of the report. Imagine you are trying to 'sell' the system to a potential customer, and hence you need to really get into it and explain what's so great and useful about it.

 

[mijoe]

Another possible answer to the first question is that Item and Item number fields effectively serve the same purpose. Therefore it would be pointless in having the same field twice creating data redundancy and wasting space.

The first poster answered the question well but missed out on including the primary and foreign keys and writing whether the relationships are one to many or many to one.

You need to include a title, header, some data as an example, column subheadings, date of the report, footer with page numbers and other less necessary things such as a border. Commentary and notes prove worthless in this question as they are not in the guideline. This is unless your diagram is insufficient. Make sure you label everything correctly.

 

[harryboyles]

Another possible answer to the first question is that Item and Item number fields effectively serve the same purpose. Therefore it would be pointless in having the same field twice creating data redundancy and wasting space.

That would be right only if each item was different. If, say, there were two video cameras, then there could be major problems.
N.B. Having reread the diagram, this is overcome by the fact that multiple items are labelled #1, #2, etc.

The point of having the item number is to increase the efficiency and reliability of the database if/when the table gets normalised. If the name of the item had to change for some reason, then it would need to be updated throughout the databse. The item number is very unlikely to change. Plus, it is more efficient to store a small number than a large string representing the name.

 

[always.dreaming]

1) the two zeros infront of the item number are redundant (i.e. 001, 002, 003) etc, especially considering that the library's catelogue of items seems so small.