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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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
262 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
4k views

What is Atomic Relation in First Normal Form

I have read the definition of 1NF which is, "If each attribute of relation is atomic". Please tell me what is Atomic.
6
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4answers
4k 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
426 views

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
150 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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284 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
87 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
252 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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0answers
83 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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2answers
379 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
229 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 ...
2
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3answers
715 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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3answers
350 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
2k views

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: ...
2
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1answer
889 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 ...
2
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2answers
529 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
152 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 ...
2
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2answers
126 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 ...
0
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1answer
223 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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3answers
3k 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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1answer
106 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
213 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
471 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
275 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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2answers
403 views

Question regarding 2NF partial key dependency

If the functional depencies are AB-->CD BC-->D IS the relation still in 2NF?,I mean since AB is the key and the 2nd BC,out of which B is part of the key,is the relation still in 2NF??
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0answers
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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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1answer
140 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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2answers
514 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 ...
3
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1answer
645 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
95 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
566 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
169 views

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 ...
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1answer
334 views

What is best practice to organize / normalize database tables?

I manage group that uses a database that is about 12 years old. There are more than 200 tables / views that have been created by various people over the years, many of them no longer with us. Most ...
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1answer
31 views

Stroring a type of an entry

There is a table estate with numeric fields districtru and districthe (for a name of a district in Russian and Hebrew), which refer to primary keys of the table districts. The districts table has the ...
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1answer
146 views

Most efficient way to structure segmented data

I am faced with a set of data which I am currently unsure on how to store efficiently. The data in question relates to a calendar which stores information on two different categories of event which ...
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4answers
285 views

Does my table violate normalization rules?

I am developing an emulator for a game. My item table looks like this: -- ---------------------------- -- Table structure for `items` -- ---------------------------- DROP TABLE IF EXISTS `items`; ...
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2answers
64 views

How to change type from one owner to two different types of owners

I currently have (tables changed): User UserID uniqueidentifier, CompanyID uniqueidentifier, (for future reference) .. more unrelated fields (PK: UserID) UserRating UserID uniqueidentifier, ...
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1answer
134 views

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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1answer
876 views

Database Design for Questions and Answers

I'm building a website that will host a variety of questionnaires. Each questionnaire has a different number of questions and each question has a different number of answers. I have attempted to ...
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1answer
181 views

Mobile Phone & Tariffs

I have designed database tables of Mobile Phones & Tariffs. It should support multiple mobile networks, sale type and the related affiliate. Points (for operators) are vary depending on the ...
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1answer
342 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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1answer
1k 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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2answers
704 views

Database normalization: Describing trait - foreign key to table, or varchar field with value?

My colleagues and I are having a discussion about the normalization of descriptive traits in the database, such as "status" or "type". Let's call the central table of the discussion "Order". In my ...
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1answer
215 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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2answers
142 views

Which tables to create according to relations

We are planning a new system with a new DB (MS SQL Server). We have the following entities and the following relations: Entities: Clubs, Chains, PaymentTypes, etc... Relations: Clubs-Chains (M-M); ...
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2answers
236 views

Writing to a DKNF database, but reading from a de-normalized table for performance?

Would the following approach be reasonable? The Goal: queries have to be relatively fast, but without the hassles incurred by writing to a de-normalized database. The Context: A database for ...
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2answers
2k views

Is one-to-one relationship normalized?

Consider we have a large set of statistical data for a record; e.g. 20-30 INT columns. Is it better to keep the entire set in one table as they all belong to a record OR creating a another table ...
3
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1answer
115 views

Reporting Table Design

I'm writing a system that allows users to store values against each week in October and November and each day in December - starting from the first Monday. I'm holding the raw data entered by the ...
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3answers
395 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 ...