Questions tagged [database-normalization]

Database normalization is the process of organizing the fields and tables of a relational database to minimize redundancy and dependency. It removes insertion, deletion and update anomalies. Normalization involves decomposing a table into less reduncant, smaller tables without losing information.

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Dependency preservation, based of original functional dependencies or canonical cover?

Given these functional dependencies for R: {A,B,C,D,E,F} AC->EF E->CD C->ADEF BDF->ACD I got this as the canonical cover: E->C C->ADEF BF->C And then broke it down to Boyce ...
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Insertion anomoly with many-to-one relationship

Suppose I have a table called "student" with a single column "name". And I want to store a second attribute called "group". "group" will be a value calculated from the name, and different names can be ...
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SQL schema trade offs for adding columns with a lot of nulls

We have decided to add a new column to our database to contain some data that used to be a substring of another column. The simplistic design is to put it into the table where it would have been had ...
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Normalized ER Diagram - Delivery System

I need to create a normalized ER diagram, but I'm having so many problems to understand normalization. The company Food and Cia delivers meals in the delivery system and wants an information ...
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ER - normalization

I need to create an ER diagram, but I'm not sure if it is correct: Consider the following description of a requirement and develop a standardized ER diagram: A pharmacy wants to record your sales ...
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Determining 4NF on a relation

CustomerOrder (custNo, custFName, custLName, orderNo, orderDate, prodNo, prodDesc, itemNum, quantity, cCardNum, paymentDate, amountPaid) The Functional Dependencies: • custNo does not functionally ...
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Sql with json, dynamic multiple product type with dynamic multiple attributes with multiple collection values

I’m looking for best practices to create ERD (SQL Server) in 2019 for following example. I have a multiple products (car like renault, opel) - about 100 000 records. Each product has series e.g (clio,...
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How do I place a table in 4NF?

I am trying to put an Employee table in 4NF but I am not sure if I am doing it correctly. Table: Employee (EmpID, EmpLastName, EmpFirstName, Phone, OfficeNumb) 4NF: Emp_LastName (EmpID, ...
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Designing simple 3NF database in SQL

Having some trouble with designing a simple database for storing currency rate. It has to include date, bank, time and rate. All the other info may be optional. With what I have I decided to break it ...
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Is my actual Relational model good design to 3rd normal form or no and what is wrong? [closed]

Please see my model to see if it is well designed to the third normal form. My relational model: person (#id_person, first name, last name, date of birth, telephone, id_work_time) person_reason (...
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How to best represent an attribute that appears in both master and detail records?

I have a simple master-detail relation in which both entities share an attribute (which happens to be a timestamp, and is not part of the key.) The detail records are ranked (by some other attribute) ...
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how can i solve this problem i cant make any normalization :(

here is logical design A B C D E F. and here are options. A->C,F / C->D / B->E problem is "how can i make 2nf? 3nf? bcnf? " i made prime key as A . here are my tried examples. i ...
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How to normalize a booking system

Basically i am supposed to build a booking system, where a user can buy one or more tickets at once, but I'm not so sure about the way we normalised the db. I mean how could I uniquely identify each ...
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Rewrite relation in second normal form

I have the following relation: Theater = (theaterID, viewerID, viewerAge, room) theaterID and viewerID are the primary keys. I know that it is not in second normal form because viewerAge is ...
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Make Into First Normal Form

Given the following relation: school =(teacherID, list of kids) I need to convert this to First Normal Form. My thought was that I have one table for teacherID then have a kids table with each kid ...
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Normalization generates a table with no clear purpose

Overview I have an assignment regarding database modelling in which I have to model a database for a shop. When normalizing from 0NF to 3NF, I end up with a table whose attributes do not seem to be ...
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UNF, 1NF, 2NF and 3NF for this table?

I am trying to figure out the UNF-3NF for this specific table. Often when i am given normalization tables, their value usually repeats throughout 2 columns at one point of the table. In this table, ...
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Is this 3NF decomposition done right?

The relation R(ABCDEF) is given with the following functional dependencies: A->B B->C A->D A->E,F E->F State the strongest normal form this is in and then convert it into third ...
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Is this in BCNF?

Assume that the relation is obtained through decomposition from a relation with attributes ABCDEFGHI and that dependencies over ABCDEFGHI are listed below. R(A,B,F) B->E A->F We need to convert this ...
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During web page display for database output use 1nf normalization or 3nf?

Firstly a bit on my project, it is my school project on making a database system that has a web page for admins and normal users to use. This database is for the school shop which sells uniforms pens ...
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Alter table commands take so long to execute

I'm trying to create 4 table hierarchy - Sport Category, League, Team and Player. Till this moment this is what I have created: -- Create PLAYER table create table PLAYER ( PLAYER_ID ...
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computerised cab service management system

Cab service company employees are categorized into sections. Each section has a section manager. Section No and a fixed basic salary rate is assigned to a section. They keep data on Emp-no, NIC No, ...
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Why is the following table in the 2nd normal form?

Here`s my table in the 1. Normal Form with the Primary Keys Student_ID and Course_Nr: Here's my table in the 2. Normal Form: For a table to be in the 2nd normal form, it should NOT have partial ...
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Database Normalisation SQL

I need to normalise this table to 3rd normal form. Clearly showing the stages of 0NF, 1NF, 2NF and 3NF. State any assumptions you can make Use relational symbolic notation.`Normalisation I have made ...
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Is this normalized correctly?

I need to normalize this database. This is for an application that will be allowing users to sign up for gaming tournaments that will be hosted at actual locations. When you search for a tournament ...
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Database Normalization steps

I am starting to learn about databases and normalization. The exercise I am addressing at the moment has an unnormalized table and I have to outline the steps to go from un-normalized to 1FN, 2FN, 3FN....
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Is this table in first normal form?

I am currently studying SQL normal forms. Lets say I have the following table the primary key is userid userid FirstName LastName Phone 1 John Smith 555-555 1 ...
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Can a table have columns that are not dependent on primary key, and still be in 2NF?

I am new to databases and have been learning about the normal forms / database practices over the past two days. I have created the following mock-up table for aircraft inspection data, but I am not ...
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Should i make seperate tables for each album?

I'm working on a database project about music and albums in MySQL, where i make a list over some popular artists, their most sold album, and the songs contained within them. But i suddenly got really ...
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Duplicate data vs Calculated data in database

I'm starting to track a host of variables around my life (QuantifiedSelf). I have a lot of input sources, and I'm working on sticking it all into a database. I plan on using this database with R to ...
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Usage of Σ and Σ+ in Normal Forms

X → {A} ∈ Σ+ : X → {A} is trivial or A is a prime attribute or X is not a proper subset of a candidate key. According to the above theory consider the following example. R = {STUDENT#, FACULTY, ...
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Confused on how to go from 2NF to 3NF

As the title states. I have read many articles trying to wrap my head around this, but am still not sure if I am doing it right or not. I think I am getting the hang of it, but wanted to get some more ...
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Avoid Duplicate Data in Postgres with Lookup Table

If I have a table of installed equipment with make and model, where the make and model will be duplicated a lot, but with a variety of spellings, etc, how is the best way to avoid wasted space from ...
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PostgreSQL: JSON column or one-to-many table for config options

We currently have a table which stores information about users. Some of the columns hold information such as user ID, name etc., but many other columns (booleans, integers and varchars etc) hold ...
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Optimized structure for normalization of multi value attribute

Suppose I have a table in which I have a column which is multi-valued, these values are primary key of another table, now I could normalize this by making it single-valued column and repeating the ...
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SQL - Normalizing a table containing multiple choices

I trying to create a database that includes a table, which will have the answers to a multiple choice quiz.. My problem is that, is it normal to create a column for every question? I mean like if I ...
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Is the example in wikipedia about 3NF conform it?

This is screenshot from the article about normal forms taken from Wikipedia. There is stated that in order to conform 3NF the Genre Name column must be put to it's own dictionary table. My question ...
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Is saving disk space still considered to be an advantage of Normalization?

I have read a while back that one of the advantages of Normalization is to save disk space (since Normalization minimizes redundancy), but is saving disk space still considered to be an advantage of ...
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Storing single form table questions in 1 or multiple tables

I have been coding ASP.NET forms inside web applications for a long time now. Generally most web apps have a user that logs in, picks a form to fill out and answers questions so your table looks like ...
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SQL: Tips on structuring table to fit 3d data?

I would just like some guidance on database optimization. I have what is essentially a daily survey with a couple sliders (so float 0-1). Each day, X amount of people from the same company will fill ...
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Database normalization - 4NF

I have the following relation and I need to normalize it to 4NF. Relation First I've tried to find all the FD's and MVD's that hold. AB ->> C (MVD) C -> D (FD) D -> E (FD) ABC -> ...
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How can I add fields named Latitude and Longitude using GeoFire in Firebase?

I'm developing a Location Tracking App with Android Studio and need to store coordinates in a normalized manner (One Variable in One Field). Can I modify the location data created by GeoFire in ...
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Dependency Preserving Decomposition with a functional dependency doesn't appear in the sub-schema

I'm reading a textbook containing the following question: Given the following relation R {A,B,C,D,E,H} and the functional dependencies AB->CD, BC->D, C->H, D->HB, CH->AE does the ...
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Is this the most normalised Database Entity Diagram I can use?

Recently I learnt about database normalisation and how it helps stop redundant data being added to a database etc. I was a little confused on how to normalise the database, is anyone able to tell me ...
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How to handle multi dimensional matrices in SQL?

I am just learning to use relational databases, so my knowledge is limited. I have data points, that rely on 3 values: Product type, age and a value x. So for each product type, there is a matrix from ...
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Normalization leads to too much queries?

Design 1: database design 1 image More tables. Better normalization. Data clean/better grouped together. Questions 1: If a user is registering an account, doesn't that do too much queries? INSERT ...
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BCNF: Looking for example that actually uses superkey instead of candidate key

The definition of the Boyce–Codd normal form states that the determinants of all non-trivial functional dependencies have to be superkeys. All the examples for relations in BCNF I found make use of ...
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Have I done this database normalization question right?

I'm learning database normalization, got a question but don't know if I've done this correctly or not. Here is my solution:
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In BCNF definition, why is “Superkey” given , instead of “minimal Superkey”?

In wikipedia BCNF definition is as follows A relational schema R is in Boyce–Codd normal form if and only if for every one of its dependencies X → Y, at least one of the following conditions hold: ...
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How relation can be made of parent and child from one “user” table in laravel

I'm making an school management system , I m told just to make one "user" table instead of making different tables of student, parent and teacher. I m confused how can I register student with relation ...

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