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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Normalize to 3NF Question - Postal Codes/City [duplicate]

Normalize to 3NF and design an ERD for the following data: Name Street City Province Postal Code Home Phone Cell Phone Just want to see if I am doing this right. PERSON NameID Name Phone Number ...
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55 views

Users vs. People - where to keep the email address?

I'm designing an app similar to Facebook, called Headtome. I want to have users that create public profiles, including email addresses. Then, Mary can choose to message John, and that message goes ...
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1answer
106 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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888 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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Anomalous Updates in Normalized Database

I've been trying to understand the three first normal forms of databases and seem to be missing something: Imagine a database with one table consisting of dances. There are 5 attributes: A Dance#, ...
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Decomposing a relation into 3NF/BCNF

I am having trouble decomposing a relation to 3NF/BCNF. I have determined that for the relation: R (A,B,C,D,E,F,G,H,I) where: {A -> B,C} {E -> F} {D -> I} {A,D -> G} {G -> H} ...
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2answers
125 views

Database Normalization

If someone could guide me on helping me understand if my results are correct I would appreciate that. Let's say I have the following table: BOOK (BookTitle, AuthorName, BookType, ListPrice, ...
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4answers
92 views

Normalization for postal addresses in US (address, county, city, state, zipcode)?

I've been trying to understand for the last few years which way is good for storing addresses. I've been getting "normalize all the way" but also "denormalize as much as you can" and I just cannot get ...
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1answer
132 views

Storing created/retired dates for a large amount of different entities

In the db I'm working on now almost every entity has these 4 columns: CreatedDate CreatedBy RetiredDate RetiredBy Usually this is used for logging purposes, and for some of the entities the ...
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1answer
136 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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39 views

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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1answer
209 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
133 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
111 views

Is it ok to create additional column for helping other column to be a PK?

Let's say a Person can have more than one nickname. He(she) must enter his(her) nicknames alongside with other details: Here is the table columns: User_Id, Nickame, Age Of course, for now there ...
2
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4answers
75 views

Row for each date, or 31 columns?

Currently I have a system whose front-end looks like this: The following query: SELECT `l`.*, `s`.`month`, `s`.`year` FROM `summarylines` `l` JOIN `summaries` `s` ON ...
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1answer
32 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, ...
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1answer
40 views

Problems in Choosing Foreign Keys :S

I am designing my very first relational database. I am now in the conceptual design, building tables and views, selecting the primary and foreign keys and normalizing everything. But now, I am stock ...
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35 views

Am I right about this normalization form?

A given schema R (A,B,C) where A->B, and B->C. a) What normal form is R in? b) If R can be normalized any further please normalize it. My answer for part a) 3NF and b) boyce-codd normal form. Am I ...
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1answer
52 views

Is a normalized MYSQL DB faster than one organized with comma strings?

I've always used databases with comma-separated id strings, something like +------+--------------+ | id | users | +------+--------------+ |1 |2,4,5,6,12 | +------+--------------+ ...
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1answer
30 views

Single table or multiple table design when records have a clear distinction but are queried together?

Let's say I have the following types of recurring data (all types periodically come in). Post (Title, Summary, Text, Timestamp) Image (URL, Caption, Timestamp) Event (StartDate, EndDate, Title, ...
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1answer
31 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.
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Modeling discounts - Product specific and Customer specific discounts

I have a reasonably simple database but have the following problem: I'm modeling a store + a lot of non-relevant stuff database. I have the following problem. I want to allow for specific products to ...
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2answers
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Modeling invoices and orders

I have a problem in modeling a database that contains orders and invoices. Actually it's more of a problem from a business point of view, but it's related to modeling the database nonetheless. Model ...
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1answer
44 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
31 views

Nullable Fields to Separate Table?

My website has a form page that has radio buttons yes|no corresponding to 7 questions. When the user selects yes, the user needs to specify a value (either a location, name, or medical condition, ...
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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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39 views

How to satisfy 1NF with food ingredients?

Take the below table as an example of my situation. How would you organise ingredients so that the values are atomic and satisfy 1NF? Product Code Manufacturer Product Name ...
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1answer
46 views

Duplicate records referenced across different databases

I have a table holding 'People' data (about 70K records) that coexists with an 'Address' table so there's one AddressID per every person in the 'People' table. The idea was to centralize the data in ...
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1answer
48 views

Should I create a extra relation-table when I have two columns in one table referencing to one column in another table

My problem is best explained by example: Suppose I have a database about chess games and players. Which one of the following structures should I choose Option 1) player (player_id,name... etc) ...
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1answer
28 views

Big Size Database and increasing number of users [closed]

Me and my colleagues are using quite big size normalized database. Basically it's used for warehouse management and daily minimum 100 of the user perform data manipulation operations. 80% of the ...
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1answer
137 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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42 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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58 views

Is It Needed to Normalize of Date Columns

I am designing a small database with relatively small data. The question is about normalization of Datetime columns. The dates of year occured many times and should I create a Days tables with a ...
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53 views

Find the Minimal Basis

Suppose we have relation R ( A ,B ,C ,D ,E ) , with some set of functional dependencies, and we wish to project those functional dependencies onto relation S(A, B, C). Given the functional ...
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57 views

Find the functional dependencies that hold in a relation

There is a question in my book that asks the following: Suppose we have relation R ( A ,B ,C ,D ,E ) , with some set of FD’s, and we wish to project those FD’s onto relation S(A, B, C). Give the ...
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36 views

3NF to BCNF without loss of any FD?

Can you provide an example of a relation which is 3NF, but not BCNF; and while breaking the original relation into two (or more) relations, no FD loses?! Tanx.
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Lose some FDs in 2nf normalization?

Suppose we have R=(A,B,C,D) and FDs are {B->C, C->D}. The only candidate key is AB, then A and B are prime; C and D are not prime. B->C breaks the 2NF requirements because is a partial dependency. So ...
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Superkeys of this relation

I am trying to find the superkeys of this relation, but I am having troubles finding out how many superkeys there are and exactly what they are. I figured out that the candidate keys were ...
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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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44 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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51 views

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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1answer
78 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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44 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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37 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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1answer
27 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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49 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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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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59 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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1answer
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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 ...