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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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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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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16 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 ...
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What and How is the ID antipattern?

What is the ID antipattern and why / under which circumstances is it considered an antipattern? The id antipattern is having a unique ID column in each table. The ID is generated for each new ...
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Closure set of functional dependency

Can anyone tell me what is the use of finding the closure set of a functional dependency? I know how to find F+ from F but don't know the use of F+.
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485 views

What are the pros and cons of using my customer codes as a primary key?

I am designing a database for one of my sales teams. Right now, the goal is to get a master list of customers and their mailing addresses, but the DB will eventually expand to track some other ...
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56 views

DB Design: Looking for Performance improvement with a Column used in all SQL Queries

I recently got added to a new ASP .NET Project(A web application) .There were recent performance issues with the application, and I am in a team with their current task to Optimize some slow running ...
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67 views

Train Fare Database Normalisation

I have a database to normalize. The database has details of train ticket fares. The trains have different fares depending on the distance and I have to store these fares in the database It is not an ...
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30 views

Building dependence between regional data (Street -> City -> PostalCode -> Country)

I'm in the process of designing a database to contain regional data to be used inside a CRM system. So, a user suspects that things like the city or country are automatically filled (or maybe just ...
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56 views

Best way to create relationship between multiple tables

I have a question about how to best handle a table that would be shared among multiple relationships, but shouldn't really be joined with all these tables. For example, suppose I have a table that has ...
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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.
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Users Characteristics

I'm really battling an issue where I have a Users table that has a growing number of user characteristics (regligion, smoking preferences, etc). The strategy I've used thus far has been to add a ...
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Is normalization advisable on transactional data?

I have read a lot of articles about normalized vs denormalized schemas, but I find very little mention of the cost of row insertion. I am considering the impact of converting a 100% denormalized ...
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How to break table into two without losing performance?

According to http://stackoverflow.com/a/174047/14731, splitting away infrequently-needed columns frees up the cache allowing faster retrieval of the commonly-used columns. I've got a table whose ...
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28 views

Denormalization Strategies: When is it appropriate to create redundancy for faster querying?

So I sometimes see databases purposely add redundant information for faster querying. I saw that this was mentioned here but I was wondering when would this be better than indexing, or creating a ...
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4answers
751 views

What normal form does a surrogate key violate?

I have following question: "What normal form does a surrogate key violate?" My thought was the 3rd normal form, but I'm not quite sure it's just an assumption i am making. Could someone explain that ...
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Identifying functional dependencies

I'm having trouble understanding the logic in use for identifying functional dependancies. Looking at the sample relation below, I understand fd1 - fd3. But when I look at fd4 and fd5, its logic ...
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48 views

Is this SQL schema normalized according to 3NF?

This schema is for a sports statistics/data app Note: Pink background = string/char/varchar Yellow background = int/tinyint Green background = dateTime bold column = PRIMARY key id_* = FOREIGN ...
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Creating a table with many optional fields

I am a developer (student) looking for some advice on what best approach should I follow while creating a table to model an entity that has a number of optional fields. There exists a need to model ...
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1answer
58 views

3NF Decomposition - I'm not sure about this example

I am trying to make sense of an example of 3NF decomposition using the 4-step algorithm mentioned by Ullman here, but I'm not understanding what my lecturer is doing with the last step (or, worse, I'm ...
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Is database normalization dead? [closed]

I've been brought up old school - where we learned to design the database schema BEFORE the application's business layer (or using OOAD for everything else). I've been pretty good with designing ...
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58 views

Normalization of Time Series Data

I have a table containing various a/b test experiment performance on a daily basis. The table structure looks something like this: date | experiment | user_count | user_attr | sales ...
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31 views

Move Commonly-Repeated Fields into a new Table

I'm still at the design stage for a new system, and I've noticed there are several places where different types of object share similar fields. In this case, we have customers, offices, warehouses ...
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database normalization to 3NF [closed]

I am just at a complete lost. I need help with this. There should be 12 tables (or perhaps 11 since one table has just a single attribute) when you are finished with the normalization and merging of ...
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How can I maintain old information after an update?

I am having an issue figuring out a solution to not lose old information. For example, customers can place many orders. Let's a customer, Mary, makes her 1st order in 2013. Fast-forward to 2014, ...
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201 views

Functional dependencies and candidate key example [closed]

Hi there I'm still learning for my examination and I got this exercise: A table is given: F-Name, F-Nation, Team-Name, Team-Nation ...
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52 views

Normalise for a very small database?

I am designing a very small database (c. 250 rows). I have a number of datapoints for each record, which under normalization rules, ought to be in separate tables. For instance: Percentages of a ...
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Trying to get BCNF out of this relation

The table is: Employee ( EID, Ename, PID, ProjectName, MID, ManagerName ) For the functional dependencies I got: EID==>(Ename) PID==>(ProjectName) ...
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Database Normalization - Can one field point to another?

This may sound like a dumb question, but I am a software developer new to database design... So the concept makes sense to me, but maybe this doesn't carry-- Is it possible for a field in a record ...
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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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23 views

Photo caption and keyword associations

I am creating a database that references images. Keywords and captions will be part of the metadata. These captions and keywords are not necessarily added to the photos with the intent of facilitating ...
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Does 3NF require 2NF?

I am a bit confused with the definition of 3NF. According to Wikipedia: The third normal form (3NF) is a normal form used in database normalization. 3NF was originally defined by E.F. Codd in ...
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38 views

Is this table in third normal form?

I have a table L(A, B, C). Functional dependencies are: A->B, A->C, B->A, B->C. Is this table in 3nf? My thoughts: A and B are keys of this table. Table is in 3nf if there are no transitive ...
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29 views

Transforming table to third normal form

I have a table like this: L(A, B, C, D, E) and functional dependencies are: AB -> CDE , C -> D, D-> B, D -> E. I need to transform this table into 3NF. I think it's not even in 2NF. I found 3 ...
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Users_With_Messages Table normal form

I have the following tables in my database: Above these tables (not pictured) is a Users table where the SendingUserId and ReceivingUserId are keyed onto (they are foreign keys). Are these tables ...
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Does this break normalization?

I have an order table, and in the order table I have a contact_id. Now, each contact is linked to an account. For my order table, should I have both contact_id and account_id? If I wanted to say, ...
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Normalization of irregular relations?

I have two tables in MySQL: The orders table CREATE TABLE `orders` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT, `transaction_id` varchar(20) COLLATE utf8_unicode_ci DEFAULT NULL, `task_id` ...
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When normalizing a relational database, should multiple “type” tables be combined into one?

Before making substantial changes to the content, functionality and design of my website (I'll be refactoring everything, almost a complete rewrite), I'm setting up a new PostgreSQL database to hold ...
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44 views

Decomposing table into BCNF that preserves dependencies

I have a relation like R(A,B,C) and dependencies like A->B , B->C , A->C I think the relation is in 2NF as candidate key is A. AFAIK when there is only one candidate key then the ...
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Decomposing into 2NF

I'm currently studying normalization. I know how to normalize the data for given unnormalized list. But I found this question in our past papers. I don't know how to answer to it. Q. Decompose ...
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Normalization is Ease to use or Creating indexes without Normalization

I'm confused in modelling the database my requirement is Below two schema's I thought to implement #1 First colleges(id,name) col_course_relation(colleges.id,courses.id) ...
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Is two unrelated tables with foreign keys to a third table breaking first normal form?

I was wondering if this breaks first normal form. AddressTable Id - PK Street City State BusinessTable Id - PK BusinessName AddressId - FK PersonTable Id ...
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Airport Database Design guidance required

I am trying to make a generic database for airport management and DBMS would be oracle 11g xe. Since, i am amateur and still learning so i have tried to kept the problem statement simple with limited ...
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Confusion normalizing data to 3NF and transitive dependencies

I am currently in a Database class and have some confusion with normalizing to 3NF. I have one specific issue that was not addressed in class but appears in the book problems. For example I have R ...
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75 views

Rules for Decomposition to 2 NF

I am struggling with the concept of 2NF form. Lets say I have a set of functional dependencies for R1(A,B,C,D,E,H,M,K) Where : B -> M,C AB -> D DH -> E H -> K A -> H Whenever I ...
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loading k:v pairs from DB into JS Object

I'm creating a single player web RPG. I'm debating the following method of storing/retrieving quest items per player id: In userstats table, have a quest_items column of type mediumtext, where I ...
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718 views

Airline reservation system [closed]

I'm making a simple airline reservation system. But I'm not sure about the design decisions I made. Concretely, I'm trying to implement following constraints: each Aircraft can have one or more ...
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96 views

Database normalization tables

I am creating a database for a very basic website. I have created the tables and put what I thought might be the correct schema, however I am having doubts about it as well as a couple problems. All ...
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32 views

Normalization to BCNF help needed

I have a table with 5 columns as A, B, C, D, and E. The functional dependencies are: AB -> C,D,E BCD -> A BCE -> A,D BD -> E I think AB is the candidate key. I can't find any other candidates. ...