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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3
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2answers
175 views

Is this in 1NF?

I'm an A-level Computer Science student, and my teacher can't explain how to get me from UNF to 1NF. I've researched a little, but I'm not sure as to whether this table (below) is in 1NF or not. I've ...
0
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0answers
75 views

Hard dba case [schema to store delivery prices for shops]

I want to make a database scheme which would allow me to fetch the delivery price for the different Shops basing on the delivery destination (Address/Region) and order value (price). Here is the ...
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0answers
36 views
1
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0answers
27 views

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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0answers
44 views

How to map this ER model to actual tables?

Suppose we have an ER-design problem like this: A pharmaceutical company sells its products throughout a country. For the ease of sales, the entire country is divided into some Areas. Areas have ...
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1answer
112 views

Expanding contractions/number ranges into separate records [closed]

I am planning the migration of a directory of image files plus a FileMaker-database containing the corresponding metadata into an Imagic IMS database (formerly known as ImageAccess). The vendor ...
1
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0answers
25 views

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 ...
1
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1answer
48 views

Need help on database design

I have a huge database of library system but I have a problem on how to design tables on this database. This is because I have under one entity (for example AUTHOR) a lot of repeatable fields. So I ...
0
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1answer
110 views

Normalization from UNF to 3NF

I keep getting confused trying to normalize this data. A company makes and sells a product online. There are ten types of Products, each having a code and price. Their Sales Order department takes ...
0
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1answer
22 views

Should i separate ContactInfo (sub-entity) from MyTable (main-entity) or Not?

I am designing a database of a school management system. I have one to one relationship of MyTable with ContactInfo table. I am confused whether I separate contactinfo from MyTable or not. ContactInfo ...
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0answers
88 views

Exam question about BCNF

I am trying to unravel the following question about BCNF from a past exam paper that is available online. The question, which is on page 7 of the linked PDF, says: Suppose that R(A,B,C,D) is a ...
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0answers
30 views

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 ...
1
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1answer
66 views

How to satisfy 2NF and what are superkeys? - Understanding the algorithm for database normalization in general

Given the table: Student_subject(studentid, subjectid, username, grade) Primary key consisting of a combination of: studentid, subjectid Candidate key consisting of a combination of: ...
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0answers
30 views

Finding the closure of functional dependencies?

I am working on a problem in which I have to look at the relation R with schema R(w, x, y, z), and the three functional dependencies: w -> z ; x,y -> w ;z -> y For every non-empty subset X of the set ...
1
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1answer
119 views

How is every binary relation BCNF?

So, as part of my assignment, I have to prove that any relation with two attributes is in BCNF. As per my understanding, if for a relation we have 3rd normal form and one non key attribute ...
1
vote
1answer
50 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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0answers
47 views

Creating a database to analyze transaction data for sports events

I would like to create a database to analyze transaction data for sports events. There is already a transactional database from which I can get raw data into excel. I want to transform this raw data ...
0
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0answers
72 views

How to design relationship for racing team trades?

I'm working on a fantasy racing team project. I'm having trouble laying out the schema when it comes to the team table and the trades. I think I have the race, driver, and result tables laid out okay: ...
1
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0answers
28 views

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 ...
7
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4answers
2k views

What exactly is overlapping candidate key?

Can some one please explain to me in simple terms what is overlapping candidate key ? What is overlapping as the name suggests? Consider the below relation R(L,M,N,O,P) { M -> O NO -> ...
3
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3answers
151 views

Optimisation Newbie: How much of a 'sin' is redundancy?

I've been developing for a while, but never really had to deal with DB/scaling issues before. That's suddenly changed and I've found myself in the deep end. I have 2 SQL tables, as such: VOTES ...
2
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1answer
296 views

Data normalization (from 0NF to 1NF)

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 ...
0
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2answers
80 views

Making database tables 1NF

I am creating a database for a DVD rental shop, I have various entities that are related to this question, such as Film, FilmStar. For each film, you record its unique number, title, the year in ...
0
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0answers
46 views

How do you create a custom replication between normalized and denormalized form using SQL Server

I have a table (on SQL Server 2008) that is denormalized like so: Table: PhoneNumbers Field: Partial varchar(8) -- 123-1234 Field: [Data] -- Refers to 800-123-1234 Data Field: [...
2
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2answers
62 views

Table “normalization” and tradeoffs

It's been a while since my databases course in university, so bear with me as I try to be unambiguous here. In the domain I'm working in, there are Sources and Destinations. Both have 2D coordinates ...
10
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6answers
1k views

Explaining 2NF vs 3NF with an example

I have a problem with second normal form (2NF) and I have been unable to solve it by using Google. It is making me crazy because I am a teacher and I don't want to teach wrong stuff to my students. ...
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0answers
18 views

custom field related to usergroup and products

We need to create dynamically custom fields and store values related to each user or product in database we have product table related to category table and also user table related to usergroup and ...
0
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1answer
25 views

Normalising a database for monitoring stations

I have data about monitoring stations. For now it is stored in Excel tabs. I have decided to try to make a database. It will be my first contact with databases. Here is an example how it looks now in ...
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0answers
132 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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1answer
74 views

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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2answers
667 views

2NF and 3NF How to do it

Given E(ABCDE) ABC are candidate keys Normalize into 2NF and 3NF As far as 2NF is concerned the solution is quite easy: E1(BD), E2(DE), E3(ABC) But with regard to 3NF I think I'm wrong if I say ...
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1answer
328 views

Decompose table into third normal form

Tables X and Y are given as below : X (A, B, D, E, F, G, H, J) with A and B as primary key Y (K, L, M, N, O, P, Q, R) with K and L as primary key Now we need to decompose these tables into tables ...
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1answer
70 views

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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1answer
223 views

Normal Form question [closed]

Hey guys I am trying to study for an exam and I cant seem to get my head around normal forms. here is one question: R1 [a b c] fd1: {a,b} -> {c} fd2: c -> b I know the candidate keys are {a,b} {a,c} ...
14
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3answers
8k views

How to have a one-to-many relationship with a privileged child?

I want to have a one-to-many relationship in which for each parent, one or zero of the children is marked as a “favorite.” However, not every parent will have a child. (Think of the parents as ...
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0answers
32 views

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 a ...
0
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0answers
68 views

Design database table for property listing

I want to design a database for a listing website, this is the first time I design the database, so I am not sure if I in the correct path. Here is the fields that needed in a listing, title - ...
0
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2answers
265 views

Normalising shared entities and applying constraints

I'm looking for a specific "best practice" or "pattern" concerning entities that are shared between different entities, having a relation to one of many. For example, one may have the generic entity "...
0
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0answers
28 views

Database normalization - Must all depedancies be preserved?

When converting to a higher normal form, must all functional dependancies always be preserved? for example: R(W,X,Y,Z) WX --> Y XY --> Z ZY --> W R1(B,C,D) XY → Z R2(C,D,A) YZ → W The ...
2
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0answers
45 views

Is there any literature on “re-normalisation” of denormalised data?

I'm involved in a project, the core of which might be generously described as "re-normalisation" of denormalised data. (To be fair, the initial implementation took only the first 90% of the time ...
5
votes
1answer
187 views

Decomposing a relation into 3NF/BCNF

I am having trouble decomposing a relation to 3NF/BCNF. I have determined that for the relation: R (A,B,C,D,E,F,G,H,I) where: {A -> B,C} {E -> F} {D -> I} {A,D -> G} {G -> H} ......
0
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0answers
27 views

Normalize to 3NF Question - Postal Codes/City [duplicate]

Normalize to 3NF and design an ERD for the following data: Name Street City Province Postal Code Home Phone Cell Phone Just want to see if I am doing this right. PERSON NameID Name Phone Number ...
1
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3answers
150 views

Users vs. People - where to keep the email address?

I'm designing an app similar to Facebook, called Headtome. I want to have users that create public profiles, including email addresses. Then, Mary can choose to message John, and that message goes ...
4
votes
2answers
54 views

Anomalous Updates in Normalized Database

I've been trying to understand the three first normal forms of databases and seem to be missing something: Imagine a database with one table consisting of dances. There are 5 attributes: A Dance#, ...
4
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2answers
240 views

Database Normalization

If someone could guide me on helping me understand if my results are correct I would appreciate that. Let's say I have the following table: BOOK (BookTitle, AuthorName, BookType, ListPrice, ...
3
votes
4answers
744 views

Normalization for postal addresses in US (address, county, city, state, zipcode)?

I've been trying to understand for the last few years which way is good for storing addresses. I've been getting "normalize all the way" but also "denormalize as much as you can" and I just cannot get ...
2
votes
0answers
42 views

How To Manage Random Data Without Repitition?

We have a database design problem of a Learning System. Please can somebody help us ? These are the requirements : A person can register for a module which has "n" number of questions. The person ...
0
votes
1answer
437 views

Array column vs another table when the relationship is quite small

The Data I am creating a table of cities and their zip codes for the United States. Some zip codes have a list of acceptable cities, as designated by the USPS. For example, the zip code 36613 is ...
1
vote
1answer
116 views

Is it ok to create additional column for helping other column to be a PK?

Let's say a Person can have more than one nickname. He(she) must enter his(her) nicknames alongside with other details: Here is the table columns: User_Id, Nickame, Age Of course, for now there ...
2
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4answers
139 views

Row for each date, or 31 columns?

Currently I have a system whose front-end looks like this: The following query: SELECT `l`.*, `s`.`month`, `s`.`year` FROM `summarylines` `l` JOIN `summaries` `s` ON `l`...