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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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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20 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 ...
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45 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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Normalization and multivalued attributes

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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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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14 views

Multilingual Article/ Category database design

I wasn't getting any answers over at Programmers and was advised to go over here instead... I wanted to make a design for a multilingual database and after having drawn it up have arrived at 5 ...
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1answer
16 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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29 views

Data-Duplication Vs Data Normalization. Better DB model?

I've 2 tables as follow:- Table UserProfile:- id name age gender phone city state country fb email and UserPoints Table having the following fields user_id activity_date app_point redeem_point ...
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23 views

Seeking help for my ASP Project. (ERD Correction Required)

I am doing this simple ASP project for my uni, just wondering if you can guys direct me or give me some advice. Project Idea is to create a recipe website which will allow users to add recipes and ...
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20 views

Normalization questions with non-real world examples

I have a few questions regarding normalization. I'm aware these may be terrible examples from a practical point of view, but I need to understand how normalization theory applies to them. 1) Table: ...
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17 views

Two id columns in one detail table

Let's I have two tables(I have removed some columns for brevity): ADULTS -> ID CHILDS -> ID And I have one table which includes detials about these persons like that: USERS-> ADULT_ID, ...
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53 views

Normalization for three somehow identical tables

These three tables are nearly identical. But, there are some exceptions. But, I can't find best normalized structure. Could you please help me? Here is the informations must be hold in database: ...
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42 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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52 views

Should I normalize my string arrays, or just keep it a simple string?

I am working on a project involving cards from the Magic: The Gathering game. To be of any use, I must load the basic information about each card into my database, but some of the fields may contain ...
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1answer
81 views

Reporting on a normalized Key-Value pivot

ERD & SQL Fiddle provided. We're trying to design a reporting tool for our stakeholders around a normalized Key-Value Pair model. We've tried to find a solution using Pivot Tables but can't seem ...
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50 views

Create database unique Surrogate Keys without using GUID’s

What is the best way to get database unique surrogate keys in Microsoft SQL Server when using something like “auto increment” as opposed to GUID's. The purpose is to increase performance over using ...
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55 views

Normalising Customers and Employers with a people table

At what normalisation stage is it recommend to split say Customers and Employees into a people table and then link to the unique attributes of Customers and Employees. I cant seem to find the ...
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1answer
73 views

Normalization to 2NF and 3NF

I solved this example to determine 2NF and 3NF. I would like to check if my answer is correct. Can somebody check the 2NF and 3NF of this example, please? R( A B C D E F G H I J) with functional ...
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37 views

How to normalize a table that contains a CK not included in the PK?

I have the following table. The PK is model_ID. Assuming that the modelName field is unique(that is, no two brands can have an identical modelName), there is a transitive dependency between modelName ...
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85 views

Normalizing: when to apply 2NF and 3NF [closed]

I am taking college classes in relational databases for half a year now. As an assignment get to normalize data with 1NF, 2NF and 3NF. I do not find any difficulties making my schema compatible with ...
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69 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 ...
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1answer
27 views

Using part of a compound key as foreign key

We have the following situation, in which we have three tables: Article ------- - Id (PK) - Supplier_Id - Supplier_Contactperson_Id - Name Supplier --------- - Id (PK) - Name SupplierContactperson ...
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1answer
53 views

Clarification for database creation and relations

I've trying to make database with few tables and relations between them. As I'm not very good in databases at all I need some clarifications. The idea is to connect table with table_1, table_2 and ...
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104 views

Should database be denormalized if I need an index across multiple tables

I have a catalog of album and song names. The song has a foreign key to the album table. I expect queries like: SELECT * FROM song s JOIN album a ON a.id = s.album_id WHERE LOWER(CONCAT_WS(' ', ...
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1answer
146 views

normalization NF1, NF2, NF3 [closed]

Pls I need an urgent help ,Can you create a Student school Transcript normalization NF1, NF2, NF3 in excel..... I actually need for someone to help me create a database of " Student School ...
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1answer
51 views

what should be the good normalization for the following scenario?

ITS JUST FAKE TABLE DATA TO SIMPLIFY MY PROBLEM I have tables ,, Users , shirts, pants, belts .... each will have some data... so by some research i have made some scenarios of links between the ...
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76 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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53 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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89 views

Index optimization on a view using a full outer join

Table structure: Foo FooChild Bar --- -------- --- ID ID ID Date FooID Date ...
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1answer
141 views

How to model schedule and keep good constraints?

I have some data that I am having a hard time modeling. Particularly, I am unsure of how I can ensure that I have unique data. This is for a schedule where I am assigning teams to stores. A team will ...
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43 views

Best way to store a function map

I am building a site where data gets filtered through user defined functions to create an output. It is a requirement that the functions are represented in the database as formulas. For example a ...
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84 views

Database Normal Form (financial statement)

I would like some advice on how to design the database for financial statement data which objectively addresses the tradeoffs between usability, performance, maintenance and adherence to normal form. ...
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1answer
208 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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Is it proper to make a grand-parent key, a primary key, in its grand-child, in a multi-level identifying relationship?

I'm modeling a DB for a conference ticketing system. In this system attendees are members of an attendee group, which belong to a conference. These relationships are identifying, and therefore FKs ...
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59 views

Normal Form question

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} ...
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29 views

why this FD make 3NF?

Question like this: Consider the relation scheme ABCDEF satisfying the following functional dependencies: BC --> ADEF CD --> B E --> D BC is a key and designated as primary. Explain why the ...
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1answer
91 views

Decompose Relation R(ABCDE) in 2nf and 3nf

Given relation R(ABCDE) with functional dependencies A->C B->D AB->E Given: AB is the primary key. I know that this relation is in 1NF because of partial dependencies A->C and B->D Now how I ...
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30 views

Dealing with co-dependent not null columns

Say I have a table entities (subclassed by people and organizations tables), where each entry requires a primary_email_id. The entities table looks like this: entities ======== id INT AUTO_INCREMENT ...
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114 views

How does one know when to stop normalizing?

Alright, so basically I feel that I tend to over-normalize things, and maybe I am doing it at the cost of performance. So, to illuminate on the problem, I have created the following schema to use as ...
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53 views

Preventing duplicate data when usual normalization only makes sense for some of the records

Background I have two tables, one called issues and the other called status_checks, which both contain (among others) the field comment (VARCHAR). An issue is raised by a user when something needs ...
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Need help about normalizing database to 3NF

I am currently working on a city travel guide application which let users explore places and plan trip. In the account module, the following functions are to be considered: User can register by ...
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486 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 -> ...
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75 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 ...
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1answer
50 views

Transforming a relation to 3NF

I'm trying to transform the following relation to 3NF but can't figure it out. The relation is (a student can only have 1 major): STUDENT (StuID, StuName, Major), Primary Key = {StuID} I tried the ...
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145 views

No-SQL Database Design for restaurant app

I've been working with SQL databases all my life and I am now trying to get into the NoSQL world. I am a looking for a piece of advice on whats the best practice in order to achieve this. Suppose I ...
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217 views

One field with multiple values?

I know that what I'm asking can't be done or shouldn't be done, but I really don't know how to do it. This is the problem: 2 tables: - Drivers (id_driver, name, etc...) - Trucks (id_truck, model, ...
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1answer
557 views

Applying normalization to a relational Database (Access & SQL Server)

This question is pretty specific but I hope it can get answered on here. There is a wide range of information about normalization but I feel what I have read so far isn't as effective as just stating ...
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116 views

A question regarding the performance of normalization

I am sorry this is such a newb question, but it is one thing I am having a difficult time wrapping my mind around, and after an evening spent reading I finally just decided to ask for some ...
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58 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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32 views

Fourth Normal Form

It's been about ten years since I paid real attention to fourth normal form, and my understanding of multi-value dependencies has seriously waned. How far is this table from 4NF and why? CREATE TABLE ...