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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2answers
178 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 ...
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1answer
70 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
46 views

How much normalization is too much

I am working on designing a database for a site I am trying to build, I created what I believe to be the best normalization strategy, to limit the size of particular tables, and the number of tables ...
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0answers
31 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 ...
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1answer
130 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 ...
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1answer
54 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 ...
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0answers
73 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: ...
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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 ...
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2answers
83 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
48 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: [...
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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 ...
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 ...
1
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1answer
75 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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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. ...
1
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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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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 ...
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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 - ...
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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 ...
0
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0answers
28 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 ...
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3answers
160 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 ...
5
votes
1answer
188 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} ......
4
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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#, ...
3
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4answers
804 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
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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 ...
3
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1answer
355 views

Storing created/retired dates for a large amount of different entities

In the db I'm working on now almost every entity has these 4 columns: CreatedDate CreatedBy RetiredDate RetiredBy Usually this is used for logging purposes, and for some of the entities the ...
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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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1answer
39 views

Should I create many ID for a same Person/entity in my DB?

In my model, I must store the name of the teacher of some kids and the classroom in which the teachers work, let’s say. All of the hundreds of teachers in the schools have 1 and only 1 classroom, ...
0
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1answer
96 views

Problems in Choosing Foreign Keys :S

I am designing my very first relational database. I am now in the conceptual design, building tables and views, selecting the primary and foreign keys and normalizing everything. But now, I am stock ...
2
votes
4answers
152 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`...
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1answer
87 views

Is a normalized MYSQL DB faster than one organized with comma strings?

I've always used databases with comma-separated id strings, something like +------+--------------+ | id | users | +------+--------------+ |1 |2,4,5,6,12 | +------+--------------+ ...
4
votes
1answer
79 views

Single table or multiple table design when records have a clear distinction but are queried together?

Let's say I have the following types of recurring data (all types periodically come in). Post (Title, Summary, Text, Timestamp) Image (URL, Caption, Timestamp) Event (StartDate, EndDate, Title, ...
2
votes
1answer
105 views

I created a DB schema for a project relating to collecting comments for web pages, is relational the way to go and how are my relationships?

I'm curious if relational DB is the way to go, if the current relationships in the diagram make sense, and whether it will bode well for coding.
2
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2answers
935 views

Modeling invoices and orders

I have a problem in modeling a database that contains orders and invoices. Actually it's more of a problem from a business point of view, but it's related to modeling the database nonetheless. Model ...
3
votes
1answer
187 views

Modeling discounts - Product specific and Customer specific discounts

I have a reasonably simple database but have the following problem: I'm modeling a store + a lot of non-relevant stuff database. I have the following problem. I want to allow for specific products to ...
2
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1answer
54 views

Database Table Design

I would like to ask couple of questions regarding my schema table design. I have the following data coming from an external database where I do not have any control over it. PROD_NO PROD_NAME ...
0
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1answer
44 views

Nullable Fields to Separate Table?

My website has a form page that has radio buttons yes|no corresponding to 7 questions. When the user selects yes, the user needs to specify a value (either a location, name, or medical condition, ...
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1answer
51 views

How to satisfy 1NF with food ingredients?

Take the below table as an example of my situation. How would you organise ingredients so that the values are atomic and satisfy 1NF? Product Code Manufacturer Product Name ...
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1answer
87 views

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 ...
3
votes
1answer
56 views

Should I create a extra relation-table when I have two columns in one table referencing to one column in another table

My problem is best explained by example: Suppose I have a database about chess games and players. Which one of the following structures should I choose Option 1) player (player_id,name... etc) ...
0
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1answer
38 views

Big Size Database and increasing number of users [closed]

Me and my colleagues are using quite big size normalized database. Basically it's used for warehouse management and daily minimum 100 of the user perform data manipulation operations. 80% of the ...
2
votes
1answer
56 views

Does schema normalization enhances query efficiency

I understand the importance of normalization in reducing data redundancy and various anomalies but I am wondering if it can also enhance the performance of your query?
0
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3answers
289 views

Is It Needed to Normalize of Date Columns

I am designing a small database with relatively small data. The question is about normalization of Datetime columns. The dates of year occured many times and should I create a Days tables with a ...
0
votes
1answer
224 views

Find the functional dependencies that hold in a relation

There is a question in my book that asks the following: Suppose we have relation R ( A ,B ,C ,D ,E ) , with some set of FD’s, and we wish to project those FD’s onto relation S(A, B, C). Give the ...
3
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0answers
92 views

Superkeys of this relation

I am trying to find the superkeys of this relation, but I am having troubles finding out how many superkeys there are and exactly what they are. I figured out that the candidate keys were {A},{B},{C},{...
0
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1answer
48 views

Lose some FDs in 2nf normalization?

Suppose we have R=(A,B,C,D) and FDs are {B->C, C->D}. The only candidate key is AB, then A and B are prime; C and D are not prime. B->C breaks the 2NF requirements because is a partial dependency. So ...
2
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0answers
53 views

Method to Obtain LossLess Join BCNF Decomposition

I have been told a way to obtain loss less join BCNF but I don't know how to calculate candidate keys(also called super key in some cases) and trivial Dependency. I have been given a relation R = (...
0
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1answer
63 views

Normilsation - 2NF and 3NF

I've been through several questions and youtube tutorials, i understand that 2NF is removing the partial dependencies and 3NF is the transitive ones, but i can't get my head around how the following ...