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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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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492 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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591 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 ...
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468 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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2k views

Loading multiValued fields into Solr via flat file, and possibly value position preservation in those fields

A hobby web project of mine uses data from many sources, some flat, some highly normalized. My ETL process boils all sources down to one logical table (which is soon to include some multi-valued ...
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28 views

Design improvement on multiple references

Im having some 'perception' problem, maybe... I got this table linked multiple times with another small table and maybe is more of a personal problem with the way it looks but I feel there might be a ...
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21 views

General Definition of/for Primary Key for Table with Repeated Entries (i.e., not in 1NF)

my first post, my apologies if this does not belong here, please refer me to the/a right site. So I am looking for a general form for a primary key given a table containing non-atomic repeated ...
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33 views

is this normalization correct

is this normalization correct for UNF to 3NF
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24 views

PostgreSQL: labels vs columns

I have a data structure similar to this: date foo bar baz boo ---------------------------------------- 2015-11-18 1 null 2.5 81.0 2015-11-19 1 78.4 12.8 ...
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41 views

Need help on database design

I have a huge database of library system but I have a problem on how to design tables on this database. This is because I have under one entity (for example AUTHOR) a lot of repeatable fields. So I ...
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21 views

DATE - Normalization, a multiple ranged query, multiple inserts and multiple update

I have a booking system, airbnb style. TABLES -> prices, house, available_date A house has available days and not available days, but sometimes the days have different prices. A weekend is more ...
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29 views

Understanding Normalisation [closed]

I have a test coming up regarding the 1,2,3 and BCNF Normalisation. The biggest problem understanding I have is from how to convert from 3 -> BCNF. Firstly how to know if the tables are already in 3NF ...
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40 views

Is it recommend to create a table for addresses? [closed]

I have a table persons with the columns per_id, per_passport, per_name and per_address. Two or more persons can live in the same address (like families or room-mates) so if this happened, the data is ...
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27 views

Beginner Question: Normalization

We know that we can normalize 1NF to 2NF by removing the partial dependencies. But I saw a lot of examples only show partial dependencies with 1 one of the PKs. If a table (in 1NF) has 3 PKs, and ...
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59 views

1NF vs BCNF cons and pros [closed]

I have a clue what 1NF and BCNF are, but I wonder why should someone prefer 1NF instead of BCNF? What are cons and pros with having relation in 1NF and BCNF?
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65 views

Converting table to a 2NF relation

I'm currently going through the process of learning about database normalization & having a crack at creating my first relational database. It was going well until I hit the following problem. ...
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28 views

does solution of Normalilization causes duplicacy in NoSQL?

i am currently using mysql as a database but now i have decided to switch rdbms to nosql probably on mongoDB. i have an doubt that nosql removed the concept of normalization from database so in such ...
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78 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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78 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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121 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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122 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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32 views

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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188 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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Difference in the workload related to data-amount and search option

A couple of days ago I was asked why it is necessary to use the first normal form also for separation of names. We have a table which stores private customers (Name+Surname;Information) and business ...
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473 views

Lossy Decomposition meaning

Suppose I have a relation R=(A,B,C,D) and I decompose it into: R1=(A,B,C) R2=(A,D) then if it is said that the decomposition is lossy,then what is the meaning of that statement?I have an ...
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134 views

Can somebody check this normalisation workings i think i am missing a step or a dependency somewhere

given these two tables: and: I need to first list them as an un-normalised structure(s) then i need to identify the functional dependencies/primary keys. Once i have done this i must represent ...
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112 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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242 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 ...
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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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2answers
70 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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97 views

What model design supports both data store backed and free form entries?

I have an application where users are tracking a workflow around producing a derivative work from an existing Book. The derivative work, we'll call "BookDerivative" must have a book that it relates to ...
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579 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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79 views

How to remove data redundancy in product table if multiple suppliers are there for same product

I am designing a database where I have different products and suppliers. For example, I have a product, "mobile phone", say an Apple 5S. This will be sold through my website from different suppliers ...
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141 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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223 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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759 views

Decomposition of a relation to 2NF and 3NF

I am trying to solve this example, but for now I can't. Can somebody show me, step by step how to decompose this to 2NF and then to 3NF? R = {ABCDEF, ABC -> EF, B -> E, E -> D} key of this ...
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51 views

Normal form definitions

I've had trouble finding a straight definition of normal forms online. I don't want any examples or metaphors, just what each form is defined by in a nice format ! I believe there is more than 4 ...
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27 views

Help with some references [closed]

Kind help if anyone has detailed of what a amstrong database are and how are they useful any current important changes in this field or advice on where I may get info in which forum any link
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219 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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183 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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105 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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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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27 views

Relation in 2NF with a transitive dependency?

Tomorrow I have my final exam of Database Design but I have a doubt about the Second Normal Form (2NF). The definition says a relation is in 2NF if no non-prime attribute is partially dependent on a ...
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33 views

Database design for actions on some entity

I am making a todo list kind of a service. One todo list will have several items , that can be done/deleted/snoozed etc. Users can also add a new item to the list , delete an item etc. I want to ...
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What should be the rule for excluding an FD from consideration while doing BCNF or any other Normalization?

Let us consider this example: http://www.mathcs.emory.edu/~cheung/Courses/377/Syllabus/9-NormalForms/examples.html At the first decomposition step, it is using A -> B C D E. On the next step, ...
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51 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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577 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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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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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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460 views

Boyce Codd Normal Form understanding

I have a knotty (at least for me) problem to solve. Normalize, with respect to Boyce Codd NF, the relational scheme E(A, B, C, D, E, F) by assuming that (A, B, C) is the unique candidate key and ...