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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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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204 views

store country name or country id [closed]

I am designing a database layout for a site. Agents registering on the site will have to enter their address including the country. Later I will build a dashboard where you would be able to ...
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Duplicate column for faster queries?

The title doesn't make too much sense, but I couldn't think a better title for this problem. I have the following tables Projects id name Customers id id_project name Payments id ...
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2answers
633 views

database normalization 2nf, 3nf

I am doing homework about database normalization. I have to decompose the table into 3nf form showing the steps here is the initial table: ...
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1answer
466 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
637 views

MySQL database normalization 3NF

I have homework where I need to create simple web interface and a DB normalized to 3NF. I've chosen ISP client selfcare as my database purpose. Web interface is no problem, the normalized DB is. After ...
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3answers
1k views

First Normal Form, why is it good and how does it reduce redundancy

I asked a similar question on SO and was advised to ask the type of question here. This is for a course on relational databases. A sample problem asks "how come every table in a relational database ...
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1answer
484 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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2answers
134 views

3rd Normal Form violation?

I've got a photo review type of application, where the customer wants to have an option for the user to flag issues with the photos. So, for instance, a photo could be tagged as "fuzzy," "grainy," or ...
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188 views

Questions regarding second normal form

I understand that in order to fulfill 2.NF, attributes must not be dependent on part of the key. Now, the question is, let's say we have a relation R with a set of attributes {A,B,C,D,E,F,G,H,I,J,K} ...
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3answers
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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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1answer
5k views

Decomposition of a relation to 2NF then to 3NF

I'm currently studying for my exams and the trouble I am having is how to decompose a relation R with given functional dependencies into 2NF then 3NF. For example for the following R and functional ...
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2answers
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MySQL Database Normalization Foreign Keys. One to Many relationship. With Diagram

Here is my database design. I've been doing a lot of reading and still don't really know what I'm doing. Hoping you guys had tips! My DB will have millions of entries. Many "People" rows will have ...
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6answers
906 views

Is normalization process needed?

Well after learning DBMS as a subject i got so many questions in mind. Normalization is one of them. As i learnt it there was a lot more confusion and i found that whatever we do in normalization ...
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3answers
112 views

Column partially determining accepted values of another column, should be somehow normalized?

I have a table that describes a set of properties (yes it's metadata, in this case there's a valid reason to have it in the database); among other things I tell the type of the data that can be ...
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3answers
111 views

Normalization/normal forms - May a field describe an other field?

Like this: CREATE TABLE persons( id serial8 NOT NULL PRIMARY KEY, name varchar, -- A lot of other fields date_of_birth timestamp with time zone, date_of_birth_precision ...
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4answers
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How can a database be normalized when an optional field causes denormalization?

Suppose you have a warehouse full of widgets. Each widget in the warehouse is stored in a specific identifiable location within the warehouse. You might have a schema which looks like this: A ...
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1answer
125 views

How would I change this relational model to fit a nosql database?

Because of things beyond my control, I have to switch from a relational database to MongoDB for the advertising platform I'm helping to build. I've got a relational schema sketched out, but I'm unsure ...
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0answers
173 views

Why is dynamic pivoting not supported?

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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2answers
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Challenge: Build MySQL table that's not in first normal form [closed]

I have read numerous books and articles about database design and SQL in which it is said that a database should be in first normal form (1NF). (Some then go on to describe situations in which it may ...
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1answer
382 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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4answers
8k views

Is there a tool to check if my database is normalized to the third normal form?

I learned about normalization recently, and understand how important it is when implementing a new schema. How can I check if my database is 2NF or 3NF compliant ? Manual review is a sure option, ...
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1answer
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Functional Dependencies and Normal Forms

I'm trying to grasp the concepts of functional dependencies and normal forms, specifically first (1NF), second (2NF), and third (3NF) normal forms. The link here was extremely helpful in deciding the ...
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1answer
172 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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2answers
302 views

Refactoring/normalization - but almost empty table

I normalized a legacy DB into this structure: But I'm not sure if it is correctly normalized. I don't feel very comfortable with the almost empty filters table. The requirements A group contains ...
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1answer
98 views

BCNF when no keys are available

I have a problem understanding a particular case of BCNF. Let's suppose that we have a relation R(B, C, D) with df:{C->D}. Is my relation in BCNF and if yes why??? Is C considered as superkey?
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1answer
533 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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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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2answers
559 views

Best relational database structure for this data

I'm in the process of creating a database scheme for the following scenario: There are users Users have roles (such as "Developer" or "CEO") Roles have applications (such as "Topdesk") Applications ...
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1answer
266 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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3answers
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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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3answers
564 views

Complex query with multiple normalized fields

We have a fairly simple table structure, but with a LOT of fields per table (talking 40+). This data is initially produced in plain-text, user-readable tables, but then it is translated into ...
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3answers
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Best practices for history/temporal tables?

Suppose I have an object, with certain fields which I want to track history, and certain fields which I do not want to track history. From a normalization perspective, is the following schema alright: ...
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1answer
1k 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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2answers
890 views

Why is this relation in 3NF?

I have a relation: R4 = {{T,U,V}, {T → U, U → T, T → V}} I know from looking at the answer key that this relation is in BCNF. I'm going through the process of rigorously determining what normal ...
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1answer
215 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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2answers
140 views

How to normalize data based only on the repetitions

Given a non-normalized data table, is there a good a strategy to attempt to normalize based on repeated data? Assume we have no information about the significance of the columns. In a small example ...
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1answer
408 views

Same product name with different price in different states

Consider the price of products in the table differs in each state. If the price varies in district I also have to mention it. How can I do this for more than 5 states? product Name Price ...
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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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1answer
109 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 ...
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3answers
242 views

Does this design satisfy 3NF, and can any improvements be made?

Does this design satisfy 3NF, and can any improvements be made? If it does not satisfy 3NF - why? By improvements, I only care if it will seriously affect scalability, efficiency, etc - I'm not ...
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2answers
736 views

History table design for supertype/subtype

I'm designing an asset management database that tracks IT hardware. I decided to use a supertype/subtype design. I'm at a point where I want to track history of changes for devices. I wanted to use a ...
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1answer
323 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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0answers
315 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 ...
2
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1answer
165 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: ...
2
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2answers
784 views

Separate or Combine 2 Tables with Similar Attributes?

I have two kind of users in my business system: Customer and Employee. Both user have Username, Password, Fullname, Phone Number, Email, and other similar attributes. I have a difficulty to ...
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1answer
1k views

Normalized Table Structure for Logging

How can I normalize a table that has four columns for logging the latest activity for a single record: Created On Created By Modified On Modified By We have dozens of tables, all with these 4 ...
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0answers
102 views

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? ...
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1answer
856 views

Splitting a column to normalized table

I have a de-normalized table as Original De-Normalized Table id text 23 first,second|third,fourth,fifth|sixth I want to normalize the database to create the following tables Table 1: (Split by ...
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1answer
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I need help to migrate denormalized table content to normalized form- MS Access

I have a staff database where we are storing information in Normalized form. There are 3 entity tables and 2 mapping tables connecting these with m-n relationships However, for ease of collecting ...