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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What are the prime and non-prime attributes in this relation?

R(HIJKLMNO) L -> MNO HI -> JKLMNO J -> KL K -> H HI is a key. So, H is a prime attribute. But, H is also in non-key part. What are the prime and non-prime attributes in this ...
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55 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?
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346 views

Can somebody help me normalise this database/check my workings

I am new to database design/normalisation and functional dependencies. I have started a new database class in school this week and we have been given a worksheet that requires the following: This is ...
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194 views

Normalizing nearly identical tables

Background I'm managing a relatively small database project in which we are adding support for reporting involving status updates for items in out product table. I was bit thrown into this and I've ...
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449 views

Database design for conditional detail table

I have an expense management system for monthly expenses. Expenses are of two types: one-time monthly expenses, and daily expenses for each day of month. I have created the following tables: ...
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3k views

Simple scenario needs to go from Unnormalized Data to 3NF - Review Please

NOTE: The Question has been updated. View Edit Revisions to view original question. The scenario. An animal charity that at the moment, track their establishment's costs via a spreadsheet like so: ...
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240 views

design of maintenance database

Lets say i am designing a database that tracks maintenance of equipment. Each piece of equipment has various fields that usually don't change eg. ID, model, serial number etc. Some fields change ...
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1answer
987 views

Multilingual Dictionary Database question

Let's say someone is coding a multilingual dictionary in PHP, and he wants to let people submit both words and definitions in English and Spanish, but wants to track it so they can be filtered. ...
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1answer
18 views

Are there any schema design changes that can take a design from 4NF into a different 4NF design?

My thought/contention is that once a database schema is in 4NF it by definition can only be changed into something less than 4NF (Denormalisation, 3NF etc) and that there is no alternative 4NF design ...
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95 views

Lost (and found?) on 4NF

I'm so extremely lost on 4NF it's not even funny. I've been reading on it for literally days and, except for about 15 minutes ago, I wasn't sure that I had even broken the surface. I think I might ...
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60 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 ...
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1answer
261 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 ...
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1answer
674 views

Dependency preserving and lossless join decompositions

I have a relation: R = {A, B, C, D, E, F, G, H, I, J} And a set of functional dependencies: G = {AB -> C, A -> DE, B -> F, F -> GH, and D -> IJ} I ended up decomposing into two ...
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173 views

Confusion normalizing data to 3NF and transitive dependencies

I am currently in a Database class and have some confusion with normalizing to 3NF. I have one specific issue that was not addressed in class but appears in the book problems. For example I have R ...
2
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1answer
355 views

Normalisation of practise database [closed]

I am a newbie to database design, and I'm a bit confused about how to create a database with minimum redundancy. Suppose I have a table abc with repetition of data in it and no two rows are same. Now ...
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2answers
133 views

Relations, dependencies and normal form

I have some issues in understanding about relations and dependencies. I will show two examples and what I want to know: Assume the relation GTX {G,T,X} with the following dependencies: G,X -> T ...
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1answer
2k views

Why is a Star Schema more normalized than a 3NF Schema?

According to Oracle's documentation, third normal form schemas "may require less data-transformation than more normalized schemas such as star schemas". I'm confused, I thought 3NF is the most ...
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299 views

Does this database table violate normalization rules?

I’m working with Access 2010. I’m developing a database for a public art program – we paint large scale murals on walls. The database tracks blank walls in the city as potential sites for murals. It ...
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1answer
60 views

This database has two foreign keys going to a single field, is it in 3NF?

Firstly, here is a picture of the database diagram generated by SQL Power Architect. I needed to create a user_id pair in order to match friend requests to users, but this has given me two foreign ...
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1answer
37 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, ...
2
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1answer
73 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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1answer
53 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 ...
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1answer
51 views

Why wouldn't I put the single preferred option into its own table, instead of having a 'Preferred' column?

In similar spirit to How to implement a 'default' flag that can only be set on a single row I would like to specify that, for any given list of possible names for a business, only one of the ...
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1answer
54 views

On modeling pairs with a possibly empty second element

EDIT: I've made the post significantly shorter. I hope it's more digestible now. Consider the following schema: CREATE TABLE X ( x TEXT PRIMARY KEY ); CREATE TABLE Y ( y TEXT PRIMARY ...
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3answers
813 views

Database design for bookmark system

I am creating a bookmark system where people can save their bookmarks. Each user has its own personal page with bookmarks. A bookmark should have atleast one tag and max five. Each user can create ...
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1answer
128 views

To normalize or not to normalizde? (10 fields)

I'm helping someone to design a database and for a specific case I'm not sure. I have 10 fields - this will never change - that will always be filled and used in every query that could be coming up. ...
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174 views

Design consideration regarding state handling: how to store multiple, variable states for one entity [closed]

First I have to admit that I'm not a database professional neither are my colleagues. For a new project my colleagues and me came to a design question we couldn't really solve easily. And all the ...
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1answer
2k views

Normalisation from 1NF to 3NF

I need some guidance on normalisation from 1st Normal Form to 3rd Normal form. I have already set up my database which is working fine but needed to show some normalisation to show that I did do some ...
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1answer
517 views

3NF decomposition + database normalization

I am studying for a test and would like to know if I am on the right track to get the following into 3NF with minimal number of keys for R: Given relation R(A,B,C,D,E,F,G) and the functional ...
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1answer
455 views

Multiple values in lookup fields

I know newer versions of MS Access allow multiple selections in lookup fields. For example, if I'm collecting information on my students, I can have a field called Race with lookup values that ...
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30 views

Looking for suggestions to model a database of Electrical Components

We have a database of electrical components and I am trying to make sure I have a good design. I am not a database designer (my comfort zone is designing with these hardware components), so I am ...
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50 views

Should I move repeating foreign keys into separate table?

Idea Users can upload lots of items and send them from processing. From the upload settings I can set a channel to which the uploaded items belong to. Channel is a separate entity. Currently I set ...
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27 views

Creating UNF for multiple actions

I am creating a database design for manufacture company for my coursework. The database design should be able to do these tasks: Buy items from suppliers. (M - N) Items are used for making products. ...
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44 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 ...
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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 ...
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47 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 = ...
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92 views

Is the table in 3NF?

I am creating a relational database - a library management system. I want to show an example where I normalize the data from 2NF to 3NF. My example of 2NF looks like The definition of third normal ...
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184 views

Identifying functional dependencies

I'm having trouble understanding the logic in use for identifying functional dependancies. Looking at the sample relation below, I understand fd1 - fd3. But when I look at fd4 and fd5, its logic ...
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80 views

Problem with reaching second normal form in a database

I'm currently taking an Databases/Database server course as a part of my education, and for this week we have been assigned a simple project to complete. I'm facing a problem regarding normalization. ...
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0answers
241 views

Why is dynamic pivoting not supported? [closed]

TL;DR What is the reason that in 2013 we still can't define a VIEW that displays some pivoted data with a dynamic column set. TL;DR/2 Is pivoting data a denormalization technique? First: Not going ...
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1answer
177 views

Can I normalize my experimental data table further?

I am attempting to get a MySQL database to 3NF, but I'm unsure as to how to get there. I'm new to database design, so please correct me if my understanding is incorrect. I have 6 columns: ...
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395 views

Help with normalization - Homework

I'm confusing myself a lot here. I did this before however have never got the hang of it. So I really need help, main issue is 2nf I just get the dependencies completely wrong. So I am practising ...
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3answers
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Normalization: 'zip code' as a primary key

I've seen frequently that you should not have all address fields (zip, street, city, state, country, etc) in the same table as your user info table (pk_id, name, email... ). This would be in ...
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1answer
898 views

Record with variable number of columns?

I am trying to model a cable mapping for devices. Each device has multiple cards, and each of those cards has multiple ports. Since both the number of cards and ports vary, I am confused on how to ...
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2answers
713 views

To normalize or not to normalize for few distinct values

Assuming in a Postgres database, you have a table called party, which can have less than 5 well-defined party_types such as 'Person' or 'Organization'. Would you store the party_type in the party ...
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151 views

How to remove data redundancy in product table if multiple suppliers are there for same product

I am designing a database where I have different products and suppliers. For example, I have a product, "mobile phone", say an Apple 5S. This will be sold through my website from different suppliers ...
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1answer
479 views

Is this table in 3NF?

I have a table person with attributes: id name city state country id is the primary key. Is this table in 3NF? If 1000 people live in same city it seems redundant to store the same data for state, ...
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2answers
59 views

SQL Data warehouse and normalization forms

I don't know if it's a simple question but does a data warehouse have different rules when it comes to normalization forms? At the moment I am creating some tables in a data warehouse, and they ...
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61 views

How to design tables such that a person can work for many companies? [closed]

Database design such that a person can work for many companies?
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244 views

What and How is the ID antipattern?

What is the ID antipattern and why / under which circumstances is it considered an antipattern? The id antipattern is having a unique ID column in each table. The ID is generated for each new ...