FDs, Decompositions, Normal Forms | Smarter Dev | Page 1

grave elk Jun 7, 2023, 1:12 AM

#

I'm stuck on how to answer these questions.

#

For question 10a, I got {A, B}, {B, C}, {A,B}, {E} as the primary keys

#

10b: 3nf, 3nf, 1nf, 3nf

#

I don't know if those are correct

#

Nor do I know how to answer anything else

#

@serene marten @true heath

#

Pinging y'all in case you guys know how to do this

#

6a I got R1(S, L, A), R2(A, S), R3(B, C) as the decomposition

#

Which I think is loseless

#

and then 6b I got R1(S, L), R2(A, S), R3(B, C) which I don't think is lossless

serene marten Jun 7, 2023, 1:18 AM

#

I'm rippin diablo rn so I'll give it a look in a couple hrs or on the train in da mornin, hopefully can help tonight

grave elk Jun 7, 2023, 1:18 AM

#

Alg, anytime today or tomorrow works

#

I got an exam for this at like 1:30pm on the 9th NZ time so anytime before then would be preferred if you can help lol

true heath Jun 7, 2023, 1:37 AM

#

I think 10c is asking if D has the same functional dependencies as F

#

Why do they have to use such obtuse terminology "lossless join property" lol ain't no one talking like that outside of a college classroom

grave elk Jun 7, 2023, 1:40 AM

#

fr fr

true heath Jun 7, 2023, 1:41 AM

#

I'm much too tired to research all this rn, if I have time tomorrow I might give it a go wolfwink

grave elk Jun 7, 2023, 1:41 AM

#

Aight cheers

serene marten Jun 7, 2023, 1:54 AM

#

true heath Why do they have to use such obtuse terminology "lossless join property" lol ain...

Yep that’s the issue with these questions 😂😂 it’s like they try to make it as detached from real world as possible

grave elk Jun 7, 2023, 5:46 AM

#

I hate the name even more because it's not even related to the concept of losslessness lol. It's about when you rejoin the tables you get extra spurious tuples, not that you lose them

true heath Jun 10, 2023, 5:00 PM

#

Did you ever figure this out? I completely forgot about it 😬

grave elk Jun 10, 2023, 10:30 PM

#

Nope

#

But the exam didn't even ask that stuff so alg lol

true heath Jun 11, 2023, 12:17 AM

#

Haha makes me feel better about forgetting

#FDs, Decompositions, Normal Forms