Relational DB vs Flat File DB (1 Viewer)

[BunJai]

Can someone please answer the following questions?

What are their use?
their differences?
adv/disadv?
which one would u prefer?

thanks!

 

[Dario]

In an exam, when it asks whether the given data should be in a relational or flat file database, it apparently doesn't matter which one you choose. As long as you can justify your decision. A relational database is, however, the one that is the easiest to justify and virtually the right answer every time.

 

[BunJai]

Oh icic
hey i wanna know would there be a chance that this type of question would appear in the HSC?

 

[Dario]

Yeah, this type of question is likely to appear in the HSC. We had it in our trial HSC and it seems like a fairly common question to ask.

 

[KeN]

RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!RELATIONAL!

 

[KeN]

Sorry 'bout that...jus the trial paper asked whether the data would be better suited in a RDBMS or a FlatFile DBSM
and i chose flat file.....

If you think you can answer the question with general knowledge, think again as a IPT student. it'll usually be a trick question......

 

[amy]

as long as you can Justify your answer you will get the marks!
RELATIONAL is the easiest just compare advantages Vs Disadvantages......

 

[Nelly]

what ARE the adv/disadv of a relational/flat file DBMS

 

[user]

Advantages of a relational database:
When designed properly and normalised, eliminates redundant data which takes up space and therefore is bad. (main reason)

Efficient for the end user

Disadvantages of a relational database:
Harder to design, and may need specialists to design it and they're expensive.

Often, many normal forms are required before a fully normalised database is created

Longer creation time required

Has this uncanny ability to confuse HSC students when asked to produce the third normal form of a given database


Advantages of a flat file database
Easy to design and fast design thingy.

[/B]Disadvantages of a flat file database[/B]
Does not eliminate redundant data

The opposite of all the good things about a relational database


(NB: I made most of that up, which is quite fine because that's what the exam's about anyway)

 

[mastermind]

Originally posted by user
Has this uncanny ability to confuse HSC students when asked to produce the third normal form of a given database

Has anyone been asked to produce 3rd norm form in trials, half-yearlys etc? I'm not exactly sure what it is, and wouldn't know how to do one in the exam, as we haven't been asked this before, and its likely the rest of my class would not know either.

And, was it in last year's exam??

 

[iptteacherssuck]

jesus!!

Normalisation is out of ipt's scope. Or at least ipt teachers scope!!!

Seriously. Normalisation isn't as simple as

"Make your db as a 3NF."

That's like saying

"Start teaching ipt teachers!!!"

 

[Lwaxana]

I have told all my students to only answer it with regard to relational .. the Yr 12 course is about relational databases and whilst u maybe able to validate flat-file .. the higher marks well be achieved discussing relational.
And 3NF wont be in this year .. I bet my Betazed socks on it

 

[mastermind]

Alright then, I wont worry about it.

Thanks Lwaxana

 

[mastermind]

BTW, is 3NF by any chance the same as DKNF (Domain/Key Norm Form) - final level of normalisation??

 

[user]

Then my teacher is a sadistic freak who tried to teach us all about 3NFs because he believes in extending our knowledge beyond what is required of us.

I wish he'd actually teach the syllabus first though.

 

[hurrotisrobbo]

Originally posted by mastermind

3rd norm form

Out of curiosity... What exactly IS it? I've never heard of _3rd_ Normalisation Form. Norm it once, twice, thrice?

 

[mastermind]

That is my guess - that it is norm-ed 3 times - but how would you actually produce that in the exam - the 3NF of a database - because i just know normalisation as reducing data redundancy etc - so im just as unsure....

 

[user]

I'm not sure if this makes sense to anyone (it doesn't make sense for me because I was er... *distracted* during the lesson)

First Normal Form- Remove Repeating Groups
1. Place all data items from the repeating group into a new table
2. Place the primary key from the original table in the new table
3. The primary key for the new table becomes the concatenated key of the original table and a field selected in the new table

Second Normal Form: Remove items that are not fully functionally depenent on the concatenated key
1. Move those items that are not fully functionally dependent on the concatenated key to a new table with the respective key item
2. If other items are functionally dependent of the key of the new table place them in anew table
3. All items should now be fully functionally dependent on the primary key of the table they are in.

Third Normal Form: Remove transitive dependencies
1. Identify fields that have a transitive dependency (Dependent on a non key field)
2. Move items witha transitive dependency to a table with a key item they are dependent on
3. Insert the primary key from the new table in the original table as a foreign key
4. Consider removing calculated fields (They are dependent on the items used to calculate them)

Looking at the example on the sheet we got given, there doesn't seem to be much use in going through all the normal forms, as it is easy just to look at the unnormalised form and see which fields need to be in a different table.

 

[Lwaxana]

3NF

Let it go guys

Syllabus says we just have to teach you normalisation.
3NF is the equivalent of having been asked how to use a bandaid you explain Joseph Lister's ideas on the causes, prevention and treatment of disease.

Its for the boffins.. and those who are trying to hang onto what they used to teach in the old Computing Studies Course.

Go sweat over your social and ehical issues they will definitely be in the exam.

 

[user]

Re: 3NF

Lwaxana- wow! you're the first level headed computer teacher I have ever met.

Originally posted by Lwaxana


Its for the boffins.. and those who are trying to hang onto what they used to teach in the old Computing Studies Course.

I think my teacher is a bit of both. But he'll go on about how it's for our own good, and that that's what they'll teach you at university, how the band 6 answers extend beyond the syllabus, and if we disagree with him, he has a cry about it and goes on about how he's "taking it up the jumper" and other assorted moronic phrases.

The only thing i've learnt from him in the last two years is Blooms Taxonomy.

:angry::axedeath:

*sighs* a bit of HSC stress relief.