Normalization is the process of organizing columns into tables within a relational database in such a way as to minimize redundancy and avoid insertion, update and deletion anomalies.

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Rules for Decomposition to 2 NF

I am struggling with the concept of 2NF form. Lets say I have a set of functional dependencies for R1(A,B,C,D,E,H,M,K) Where : B -> M,C AB -> D DH -> E H -> K A -> H Whenever I ...
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927 views

Does 3NF require 2NF?

I am a bit confused with the definition of 3NF. According to Wikipedia: The third normal form (3NF) is a normal form used in database normalization. 3NF was originally defined by E.F. Codd in ...
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56 views

Decomposing into 2NF

I'm currently studying normalization. I know how to normalize the data for given unnormalized list. But I found this question in our past papers. I don't know how to answer to it. Q. Decompose ...
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123 views

UK Addresses in 3NF

I am in the process of creating a UK only database which holds information for various sets of people i.e. Staff, Clients etc. The tables for each of these sets of people have an Address, City and ...
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127 views

Given the functional dependencies of a relation is there more then one way to normalize it?

I"m studying normalization and have been reading through descriptions and examples online. One Concept that isn't clear to me is if the process can be automated at any point. I understand that a ...
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64 views

Need some recommendations on organizing data

I'm new here. This question, to my mind, is allowed by the rules I saw in the "2 minute tour". If I got it wrong, no need for nasty grams. I'll delete if enough people say so. But anyway, I have a ...
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175 views

Scheme review/Normalization level/query optimization

So I have a relatively complex database I'm designing - basically full in-house accounting setup. In one section I have some concern that I'm over-normalizing; the 'directory' - I'll example the ...
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29 views

Normal form for a relation where the number of tuples having the same value in a column is the same for all the possible values in that column

Is there a normal form for a relation that would permit the following table : id | alpha ---------- 1 | a 1 | b 1 | c 2 | g 2 | u 2 | k . . . n | x n | y n | z But not this table : id | ...
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Is this table designed properly

I am trying to model the process of where one co-worker enters a statement of their proposed work procedure and another co-worker commenting and approving the statement. Currently I have one table as ...
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307 views

Should I extract / normalize the mailing address despite requirements limiting number / type of addresses?

I currently am working on a contacts application (similar to Outlook contacts combined with eVites and LinkedIn). The requirements for the application are to limit the addresses (and phone / email ...
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2answers
205 views

How to normalize data en-masse?

Goal: Extract address fields from a users table into a separate addresses table linked by foreign key. I have created the structure below, and have millions of rows to deal with. I need to do this ...
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3k views

School database design

I am trying to design a database management system with my PHP and intermediate MySQL knowledge, keeping normalization in mind. These are the assumptions: The school has many students from grade 1 ...
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661 views

UNF to 3NF is this relation workable?

I've inherited a flat table of data consisting of around 2 million records. Looking at the data its already in 1NF, i'd like to get this into 3NF. The data is Australian so suburb can't determine ...
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how to convert a table into second normal form

I am really struggling to convert the table into second normal form ive tryed examples which are much easier however i can't seem to be able to identify the keys for this one and work my way forward. ...
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191 views

Approach to Analyzing Database Requirements

When presented with requirements for a database driven system, I always find it useful to imagine a world with no computers, where data records were kept in filing cabinets and data was collected by ...
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311 views

Does my design adhere to 3NF?

I created this schema with OpenOffice. Does this design adhere to 3NF ? (A relationship link between Equipment and Supplier_Equipment , Customer and Membership should be created but OpenOffice ...
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369 views

Are these database tables normalized?

I am developing a webapp for an institute and I designed these tables: Are these tables normalized?
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Database Design - When to use “attributes” rather than additional columns

I'm wrestling with a schema design issue. I'm attempting to determine when I should add another column instead of making it an "attribute". Rather than adding a numerous columns to a table, I ...
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549 views

Does this normalized model for artist music records make sense?

I want to make a database about one artist's music records... CD, Vinyl, Cassette, 8 Track, Singles, Ep, Lp, etc... I believe I have a good normalized model that will achieve my needs, however before ...
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605 views

shoud we normalize user profile table with fields like interests,musics,videos,sports, etc?

I've read in an article about social networking database schema and saw that they've used varchar for those columns that I mentioned in the question title. It's not normalized! Isn't it better to have ...
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478 views

Normalization: Should common columns of two tables be pulled out into a third table?

Should I further normalize my current design to eliminate redundancies? I have the following tables: empl: standard user table empl_cat: employee "category" empl_admin_cat: administrative ...
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2k views

Loading multiValued fields into Solr via flat file, and possibly value position preservation in those fields

A hobby web project of mine uses data from many sources, some flat, some highly normalized. My ETL process boils all sources down to one logical table (which is soon to include some multi-valued ...
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28 views

Is this database in 1NF, 2NF and 3NF?

I'm doing a software development course and I have to normalise my tables as part of it. Can anyone double check that my data is normalised correctly? The database is for a gym. It has these tables ...
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Is this a violation of Normal Form?

Assume a cash register system where some users have access to a cash drawer, while others do not (they can only close by some kind of card payment). Keep in mind that a user who closes a check a one ...
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Clustered index on last_update_at timestamp

I have a Votes table , which can be considered a wrapper. I have a sub_items table, which holds one votable item. One Vote has many sub_items. On sub_item is owned by only one Vote. I have a ...
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How to improve on this database design

I have different 'modules' . Currently , they are: Votes Chats To-do lists I am using mysql and long polling to get updates about these modules in near real time. I have also have a table called ...
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Help needed designing a 'Group' concept for students in a class

I've been wracking my brain for a while now trying to figure out how to fit this part of my domain model into the database, but whatever I come up with just feels wrong. I've attached a picture below ...
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Design improvement on multiple references

Im having some 'perception' problem, maybe... I got this table linked multiple times with another small table and maybe is more of a personal problem with the way it looks but I feel there might be a ...
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General Definition of/for Primary Key for Table with Repeated Entries (i.e., not in 1NF)

my first post, my apologies if this does not belong here, please refer me to the/a right site. So I am looking for a general form for a primary key given a table containing non-atomic repeated ...
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is this normalization correct

is this normalization correct for UNF to 3NF
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PostgreSQL: labels vs columns

I have a data structure similar to this: date foo bar baz boo ---------------------------------------- 2015-11-18 1 null 2.5 81.0 2015-11-19 1 78.4 12.8 ...
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DATE - Normalization, a multiple ranged query, multiple inserts and multiple update

I have a booking system, airbnb style. TABLES -> prices, house, available_date A house has available days and not available days, but sometimes the days have different prices. A weekend is more ...
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Understanding Normalisation [closed]

I have a test coming up regarding the 1,2,3 and BCNF Normalisation. The biggest problem understanding I have is from how to convert from 3 -> BCNF. Firstly how to know if the tables are already in 3NF ...
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45 views

Is it recommend to create a table for addresses? [closed]

I have a table persons with the columns per_id, per_passport, per_name and per_address. Two or more persons can live in the same address (like families or room-mates) so if this happened, the data is ...
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Beginner Question: Normalization

We know that we can normalize 1NF to 2NF by removing the partial dependencies. But I saw a lot of examples only show partial dependencies with 1 one of the PKs. If a table (in 1NF) has 3 PKs, and ...
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1NF vs BCNF cons and pros [closed]

I have a clue what 1NF and BCNF are, but I wonder why should someone prefer 1NF instead of BCNF? What are cons and pros with having relation in 1NF and BCNF?
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Converting table to a 2NF relation

I'm currently going through the process of learning about database normalization & having a crack at creating my first relational database. It was going well until I hit the following problem. ...
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does solution of Normalilization causes duplicacy in NoSQL?

i am currently using mysql as a database but now i have decided to switch rdbms to nosql probably on mongoDB. i have an doubt that nosql removed the concept of normalization from database so in such ...
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Duplicate records referenced across different databases

I have a table holding 'People' data (about 70K records) that coexists with an 'Address' table so there's one AddressID per every person in the 'People' table. The idea was to centralize the data in ...
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Normalization and multivalued attributes

I am designing a relational database in mySQL - a library management system. I want to show examples of the data in 1NF, 2NF, 3NF, BCNF, etc. My example of 1NF looks something like this 'A relation ...
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130 views

Normalized database table with non-atomic values

I'm creating a normalized table for a questionnaire that the customers fill in and in one of the columns is a field called "extra comments". I realize that with the "extra comments" field, the data ...
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135 views

DB Design: Looking for Performance improvement with a Column used in all SQL Queries

I recently got added to a new ASP .NET Project(A web application) .There were recent performance issues with the application, and I am in a team with their current task to Optimize some slow running ...
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Trying to get BCNF out of this relation

The table is: Employee ( EID, Ename, PID, ProjectName, MID, ManagerName ) For the functional dependencies I got: EID==>(Ename) PID==>(ProjectName) ...
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201 views

Decomposing table into BCNF that preserves dependencies

I have a relation like R(A,B,C) and dependencies like A->B , B->C , A->C I think the relation is in 2NF as candidate key is A. AFAIK when there is only one candidate key then the ...
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Difference in the workload related to data-amount and search option

A couple of days ago I was asked why it is necessary to use the first normal form also for separation of names. We have a table which stores private customers (Name+Surname;Information) and business ...
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564 views

Lossy Decomposition meaning

Suppose I have a relation R=(A,B,C,D) and I decompose it into: R1=(A,B,C) R2=(A,D) then if it is said that the decomposition is lossy,then what is the meaning of that statement?I have an ...
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138 views

Can somebody check this normalisation workings i think i am missing a step or a dependency somewhere

given these two tables: and: I need to first list them as an un-normalised structure(s) then i need to identify the functional dependencies/primary keys. Once i have done this i must represent ...
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113 views

Unable to decompose this relation to BCNF

I have a relation R = { A, B, C, D, E, F, G, H, I } And functional dependencies F ={ ABC -> DE E -> C AB -> F C -> G F -> H H -> IJ F -> B } I am able to do simple BCNF ...
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249 views

Database functional dependency BCNF help

I understand most of BCNF and have been able to complete numerous problems with it, I'm just having trouble applying it to the following situation: R(A,B,C,D,E) FDs: { A->D; BE->A; CD->E } Here's ...
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Difficulty in finding Candidate Keys

I have an homework which should be submitted tomorrow I normaly know normalization concepts but in some questions I have difficulty. How should i normalize this to BCNF? Can you show the steps please? ...