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.

learn more… | top users | synonyms

1
vote
1answer
151 views

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 ...
1
vote
1answer
363 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 ...
1
vote
3answers
517 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 ...
1
vote
1answer
394 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 ...
1
vote
1answer
1k 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 ...
1
vote
0answers
19 views

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 ...
1
vote
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 ...
1
vote
2answers
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 ...
1
vote
1answer
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 ...
1
vote
1answer
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} ...
1
vote
0answers
89 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 ...
1
vote
0answers
66 views

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 ...
1
vote
1answer
28 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) ...
1
vote
0answers
110 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 ...
1
vote
0answers
22 views

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 ...
1
vote
0answers
225 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 ...
1
vote
0answers
129 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 ...
1
vote
0answers
100 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 ...
1
vote
1answer
212 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 ...
1
vote
0answers
101 views

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? ...
1
vote
2answers
69 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, ...
1
vote
1answer
452 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 ...
0
votes
1answer
367 views

Is this table in 3NF?

I have a table person with attributes: id name city state country id is the primary key. Is this table in 3NF? If 1000 people live in same city it seems redundant to store the same data for state, ...
0
votes
2answers
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 ...
0
votes
2answers
571 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 ...
0
votes
2answers
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 ...
0
votes
1answer
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 ...
0
votes
1answer
97 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?
0
votes
1answer
54 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: ...
0
votes
2answers
218 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, ...
0
votes
1answer
42 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 ...
0
votes
1answer
55 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 ...
0
votes
1answer
380 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 ...
0
votes
1answer
211 views

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 ...
0
votes
1answer
439 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 ...
0
votes
1answer
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 ...
0
votes
1answer
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 ...
0
votes
1answer
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. ...
0
votes
1answer
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 ...
0
votes
1answer
559 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 ...
0
votes
3answers
193 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 ...
0
votes
1answer
108 views

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 ...
0
votes
2answers
286 views

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 ...
0
votes
1answer
95 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 ...
0
votes
1answer
86 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 ...
0
votes
1answer
35 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 ...
0
votes
2answers
40 views

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, ...
0
votes
1answer
2k 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 ...
0
votes
1answer
247 views

Attempting to identify transitive dependency

Hello I am attempting to identify a transitive dependency in the following diagram. I think that possibly the determinate of "Subtotal" is "Quantity" and "Price Charged" but I'm not sure if "subtotal" ...
0
votes
1answer
56 views

Design for hierarchical embedded database

The goal is to construct a hierarchical database of Objects having the following format: TypeA -> ObjectA [values, contains ObjectB*, ObjectC*, etc.] TypeB -> ObjectB [values, contains ...