/prog/ - Database Design

Name: Anonymous 2011-05-22 11:50

Can anyone give me a hand, i know it will be pretty basically and i've been to stack overflow already. But im pretty noob at database design/relations etc.All I need is to calculate the closure for A+ and E+

G = {A, B, C, D, E, F, G}

with the following FD's
1) B -> ACDE
2) E -> FG

Any help would be appreciated.

Name: Anonymous 2011-05-22 11:53

pretty
More like PIG DISGUSTING

Name: Anonymous 2011-05-22 11:54

oops, i meant pretty basic.

Name: Anonymous 2011-05-22 12:01

What are you? A ''computer' scientist' that cannot finish his homework?

PROGS OR GTFO

Name: Anonymous 2011-05-22 12:06

Uhh nope, just a uni student, struggling to understand database design.

Name: Anonymous 2011-05-22 12:09

accept it u cant learn anything from /prog/

Name: Anonymous 2011-05-22 12:11

>>6

Yeah, pretty much figured that. Probably all 17yo's that cant even do it anyway.

Name: Anonymous 2011-05-22 12:17

>>7
Or the Unholy Legion of Reverse Psychologists who just simply don't care.

Actually, my explorations so far suggest they're mostly first-year students going into second-year, with the most prominent regulars being eternally stuck there somehow. Database administration is a third or fourth year course at most institutions.

Name: Anonymous 2011-05-22 12:25

>>8

Makes sense i guess.

Name: Anonymous 2011-05-22 12:36

>>1
I am not sure how it works on Database Design, but given we are talking about closures, you must take the relations that they give you and expand them until you get a set of elements that cannot be expanded. Something like this, i guess:

{A} -> Cannot be expanded, therefore Closure(A) = {A}
{E} -> {E, F, G} -> Cannot be expanded, therefore Closure(E) = {E, F, G}

Treat this advice carefully since it is a general explanation for closures.

Name: Anonymous 2011-05-22 13:02

>>10

Yeah i was talking about closures. Helped a little thanks man.

Name: Anonymous 2011-05-22 13:10

>>8
Database design is a second year course at my Uni.

Name: Harold Camping 2011-05-22 13:56

wow an interesting discussion on /prog/. maybe the world ended yesterday and a split second later a new one started/.

Name: Anonymous 2011-05-22 14:26

>>13
discussion
where?

Name: Anonymous 2011-05-22 14:29

>>11
Transitive closures. Closures come in many different shapes and forms.

Name: Anonymous 2011-05-22 19:13

>>15
Well, since closures over transitive relations are the most common that you can find on every CS text, we can speak about closures instead of transitive closures.

Name: Anonymous 2011-05-22 21:47

OP: Are you in England? North of London, South of the Tee's-Exe line?

Name: Anonymous 2011-05-24 1:44

OP OP-- IT'S IMPORTANT

Name: deppricated 2011-05-24 3:35

deppricated

Name: Anonymous 2011-05-24 8:54

>>16
...well, as /prog/ is the physical manifestation Lisp Hell, we usually actually talk about lexical closures.

Database Design

1 Name: Anonymous 2011-05-22 11:50

2 Name: Anonymous 2011-05-22 11:53

3 Name: Anonymous 2011-05-22 11:54

4 Name: Anonymous 2011-05-22 12:01

5 Name: Anonymous 2011-05-22 12:06

6 Name: Anonymous 2011-05-22 12:09

7 Name: Anonymous 2011-05-22 12:11

8 Name: Anonymous 2011-05-22 12:17

9 Name: Anonymous 2011-05-22 12:25

10 Name: Anonymous 2011-05-22 12:36

11 Name: Anonymous 2011-05-22 13:02

12 Name: Anonymous 2011-05-22 13:10

13 Name: Harold Camping 2011-05-22 13:56

14 Name: Anonymous 2011-05-22 14:26

15 Name: Anonymous 2011-05-22 14:29

16 Name: Anonymous 2011-05-22 19:13

17 Name: Anonymous 2011-05-22 21:47

18 Name: Anonymous 2011-05-24 1:44

19 Name: deppricated 2011-05-24 3:35

20 Name: Anonymous 2011-05-24 8:54