Ask MetaFilter questions tagged with normalization

Getting to Yes^W 3NF

alex.dudley — Thu, 29 Oct 2009 07:24:58 -0800

Need help getting to 3NF when one attribute is functionally dependent on a combination of other attributes. I am having problems working out how to get the following situation (or similar ones) into 3NF. I know that in production we would probably not want this to get to 3NF because of the performance hit from JOINs; please ignore such things, this is theoretical.

The situation I'm struggling with is one where an attribute is transitively dependent through a combination of other attributes in the same table, and how to split that out into 3NF.

How do you get to 3NF in a situation like the following:



RoadTrip (tripID, startLocation, finishLocation, distanceDriven)

Details:
tripID is an autonumber/surrogate key
distanceDriven is dependent on both startLocation and finishLocation, because the distanceDriven is the distance between these two locations.

I have mulled this over in my head and tried to figure it out, I suspect my solution is wrong:



RoadTrip (tripID, startLocation, routeID)

FK: routeID references TripRoute.routeID

TripRoute (routeID, finishLocation, miles)

Is that really how to get this into 3NF?

I can't find any good examples of this sort of normalization situation through Google; the examples I see don't have any cases of finctional dependency on a combination of attributes.

The Hive Mind is all that's left. Please hope me normalize!

Normalize mp3s

edmz — Fri, 20 Mar 2009 15:46:21 -0800

Recommend me software, preferably free or cheap, so that I can permanently normalize and clip about 200 mp3s. I'm not looking for something automatic, I don't mind doing it one tune at a time. What I definitely want to avoid is converting mp3 to something else.

Extra points if normalizing the mp3 is something the software can do without tons of steps.

How much database normalization is too much?

EduTek — Fri, 25 Apr 2008 15:57:49 -0800

How much SQL normalization is too much? I've listened to the excellent advice in my last question and decided to start over with my web app. I went from three tables to 17, and now I find myself wondering: how much DB normalization is too much?

More specifically, if I have a status field which can contain very few entries (no more than four ever for the rest of this app's life), do I have to pull it out into a separate table?

For Example, is this:
Table: course
Fields
courseid (1)
coursename (History)
coursestatus (1)

Table: status
Fields
statusid (1)
status (In Production)

Better than this:

Table: course
Fields
courseid (1)
coursename (History)
coursestatus (In Production)

Thanks for your help!

Normalize My Audio

escher — Tue, 22 Aug 2006 10:53:42 -0800

I want to normalize the audio output of my DVD player within a certain range. Is this possible? I'm tired of having to turn up the volume when someone is whispering in a movie, only to turn the volume down when the next action scene comes along. I'd like to have it so that the movie isn't too loud or too quiet.

I know you can normalize audio on the computer - i've done it when making a mix cd from a variety of sources and i want the songs to all be relativley equal in volume.

Do any dvd players offer this functionality? I realize that to do it proper, it needs to analyze the audio of the entire dvd before playing so that it can determine the "gain" for that particular dvd. And that analyzing might take some time.

The "midnight" mode on my particular dvd player/receiver doesn't seem to do the trick, but sometimes having the DSP set to "vocal" helps bring out the talking but not the crash scenes.

Help me make music for MuFi

snsranch — Mon, 17 Jul 2006 19:08:38 -0800

Can you help me be a better home recording engineer? I've posted some things to MuFi which were pretty fun, but are technically suck-tronic. I've been making music for about 20 years, but have never recorded my work in any serious way and don't really know what I'm doing.

1. The Rig: A Shure SM58 to a Eurotrack MX802A mixer to MAGIX audio studio 2005 DeLuxe. I also use a Korg workcenter and various amps and guitars.

2. What's really killing me is mixing the vocals. Guitars and banjo with or without amps seem fine but when I try to lay the vocal tracks it just sucks.

I know there is no easy answer to this, but perhaps (even though I've searched alot) an online totorial or something might be helpful. I know there are some gurus out there, I've heard you on MuFi! Thanks in advance.

The [Title] bone's connected to the [Lyrics] bone...

Brainy — Mon, 17 Jul 2006 13:41:40 -0800

MySQL/PHPmyAdmin for a band: How do I easily create a repository of lyrics that can be brought in for multiple albums? Dreamhost server
phpMyAdmin 2.8.0.3
MySQL - 5.0.18-standard-log
(I read somewhere that "Relationships are off". I tried setting up relationships on another site and got nowhere with it.)

My database background is Access, but I feel I've got a handle on the whole normalization thing and so here's where I run into problems. A band has [Albums] albums contain [Songs] which have [Songs.Lyrics]. I would like to not have a long text field for each album that has all the lyrics (and their css encoding) - also, some songs are on a couple different albums.

But how can I set up a many to many structure without relationships?

Or how do I set it up with relationships in phpMyAdmin? All the documentation seems to say not to do it, or is so advanced, I can't tell if it's relevant.

MySQL Normalization Question

fishfucker — Thu, 27 Apr 2006 13:41:11 -0800

DBAs: Is this a case where I *should not* normalize my database? (PHP/MySQL 4.0.24 question). Long explanation of the situation inside. So here's the deal -- I'm (re)writing an app that needs to allow users to build questions which can be later used in forms presented by that application use in forms. Questions that are straightforward ("Fill out this field", "Pick from these choices") are very simple to do. However, it gets a little more complicated when you have questions like "Pick from these choices, if other, please fill out the blank" or "If the answer to question 2 is yes, please answer question 3?" -- ie, dependent questions.

I'm currently storing questions as a single record in the database. When I have multiple choices for each question, I newline-separate them and stick them into a field called "question_data". When I present this question to a user, I simply grab the question (via ID number) and explode/implode the "question_data" field into the proper HTML markup. I use an arbitrary symbol when I need to do something like the "Other" field above (although I don't yet have a way of doing the "If the answer to question two is yes, please answer question 3" but I'm sure i could write one. When I need to perform calculations using this data (ie, how many people answered question 2 with answer B?), I get all the users answers and tally up the occurence of each -- "other" responses are prefixed with an "Other: " string that is trivial to find with PHP.

Now, this solution has worked well so far because 1) doing database dumps of user demographics is pretty straightforward (I can just dump their question field directly into the report) and 2) everything is just in one field, *even* if it is an "Other" answer -- ie, if the user gives a "non-official" answer, then I don't have to go look for it.

I've been trying to read more about database design in my spare time (I am by no means a DBA) and it seems like what I'm doing with the question_data field is a big no-no. I can think of some advantages to making another table and having individual records for each question option available, but it seems like calling everything up to display the question (which is the more important thing for this app) would take longer than the way I'm currently doing things (ie, it'd be a join AND I'd have like, 25 rows to deal with).

So what should I do here? Am I looking at the problem totally wrong? Should I force normalization onto these question options? Is the way I'm using question_options already normalized?

or is this a case where I should just comma-separate the "question_data" field and upgrade to mysql 5 so I can do FIND_IN_SETs?

i realize this is a confusing configuration to explain without pictures -- I'll do my best to fill in any important holes I might have missed.

Postal Processing for Client Databases

willnot — Thu, 24 Feb 2005 14:25:06 -0800

I have a client database with about 200K records in it. Addresses were fed in by a variety of people so there're tons of typos/missing information and not much in the way of standardization. I need to do some postal processing (CASS, DSF2, LACS and NCOA) on the file. Is that something that's mostly done in software and so could be done in-house, or does it require a lot of specialized human intervention and so something that it makes more sense to outsource? If it can be done in-house, where would I look for software to do it? If it should be outsourced, what should I expect to pay for a file with 200K records?

Balancing the mix for a full album's worth of tracks

goodnewsfortheinsane — Mon, 14 Feb 2005 14:10:17 -0800

I'm mixing an album and I want all tracks to have the same apparent loudness. [that noise comes from inside] I've recorded 13 songs, ranging in style from reasonably high-octane punkish rock songs (drums, bass, electric + acoustic guitars, vocals) to solo singer-songwriter material (just vocals and acoustic guitar).

I'm reasonably acquainted with desktop audio, basic mixing practices etc. I've also recorded and mixed songs on a PC before, but never a full album.

Now the mixes need to be mastered (mainly compression and some EQ) , and I want them to have the same overall subjective volume. Tastes in compression vary, but I find myself leaning towards the "the louder the better" camp - within the limits of reason, of course.

How do I go about this? Is there a cut-and-dried method, or is it just trial and error? I understand that the subjective evaluation of tonality and volume is the main governing factor, but is there also perhaps a technical tool that could help, perhaps in the form of a tool that could measure the overall RMS of a given track?

All suggestions will be greatly appreciated.

WinAmp Normalization

LouMac — Mon, 06 Dec 2004 18:37:13 -0800

WinAmpFilter: The constant variation between too loud and too quiet is killing me. Which WinAmp plug-ins for volume normalization do you recommend? Yes, I know iTunes does it well, but iTunes doesn't play nice when I have a couple of other programs open.