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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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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43 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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51 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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22 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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36 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, ...
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219 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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52 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" ...
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1answer
40 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 ...
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39 views

How to relate 2 tables to a third when the first 2 tables have a relationship?

For once, I find myself at an utter loss in terms of coming up with a good question title. Consider the three following tables. Each has additional columns, but only the columns relevant to the ...
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1answer
85 views

How can I normalize this database?

I've got legacy ecommerce database, which is awfully designed and I need to move all products from it to new solution. But I stuck with how product properties stored. So it basically has tens of ...
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1answer
26 views

Effectively modelling extended classes

I have 3 different types of content for a website, 'Article', 'Video', 'Review'. Each of those three types of content contain common fields and type specific fields. For this, I have created the ...
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1answer
78 views

Normalise an expenditure table in a budget database [closed]

We have a budget database that stores expenditure items per budget. There are over 100 expenditure items each having common attributes: Amount, Frequency, Comment. The table will have over 300 ...
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1answer
113 views

store country name or country id [closed]

I am designing a database layout for a site. Agents registering on the site will have to enter their address including the country. Later I will build a dashboard where you would be able to ...
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3answers
99 views

Column partially determining accepted values of another column, should be somehow normalized?

I have a table that describes a set of properties (yes it's metadata, in this case there's a valid reason to have it in the database); among other things I tell the type of the data that can be ...
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2answers
426 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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1answer
153 views

Most efficient way to structure segmented data

I am faced with a set of data which I am currently unsure on how to store efficiently. The data in question relates to a calendar which stores information on two different categories of event which ...
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5 views

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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2answers
26 views

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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0answers
13 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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17 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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1answer
51 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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13 views

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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29 views

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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24 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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Functional Dependencies Query

I am having a confusion in Functional Dependencies I have a relation R(A,B,C,D,E,F) Where {A, B} is the key And the FD set I have is {A->FC, C->D, B->E} What Normal Form is it in? Basically I want ...
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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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1answer
99 views

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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18 views

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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28 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. ...
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82 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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52 views

How to convert this relation to 2NF?

In my Entity Relationship Diagram, an entity type TEACHER had a relationship of TEACH with another entity type called CLASS. CLASS was a week entity type of TEACHER,so when mapping to a Relational ...
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44 views

Normalise the database, struggling to understand how i can normalise this

Cross post warning: I recently found dba.stack exchange so i thought it would be better to post there: ...
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1answer
54 views

Maximum normalization

I have been studying the normal forms rules to guide me with database design and data storage, the problem I am having is that once I optimize for the first normal form (1NF), I figured I may well ...
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0answers
187 views

Normalizing data to 3NF

I need some help with normalization. Here is the data in 0NF : **HOSPITAL SERVICES (date_hospitalization , id_patient , id_doctor , name , surname , PIN, duration_of_hospitalization , ...
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39 views

Decomposition into BCNF where an attribute appears in multiple functional dependencies

I am trying to decompose my relation: R = (A, B, C, D, E) with Functional Dependencies F = {D -> BC, E -> B, A -> B, B -> D} The problem is that D appears in two dependencies and in ...
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48 views

3NF decomposition

Can anyone tell me how and/or why I'm getting stuck here? I have scouted around on the web for examples of 2NF and 3NF decompositions and they all seem to make more sense than the one I'm working on. ...
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0answers
61 views

Figuring out determinants when converting table into 1NF form

I have to figure out the determinants in the region for the following table. St ID L Name F Name Phone No St Lic Lic No Ticket# Date Code Fine 38249 Brown Thomas 111-7804 ...
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30 views

How to find a projection on the functional dependency?

I have below dependencies on attribute PUT: P -> QR T -> WV R -> UV V -> P Now how to find a projection on the above functional dependencies? I am trying to find a article which can ...
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1answer
26 views

Good idea to include summary of frequently accessed data from another foreign-keyed table?

Sorry for poor title, I'll try to explain it in more detail here. I have an application that often gets a row from table A, then looks up a column from that in a foreign key mapping table (table B), ...
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1answer
204 views

Normalization and Breaking down tables for InnoDB

I'm designing a web application, something small but deals with lots of read and inserts. Let's say 60% read and 40% writes. My storage engine is InnoDB on MySQL. I have a table called User which has ...
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1answer
90 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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1answer
56 views

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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0answers
20 views

Is schema always in 1st normal form?

So if schema is not in 1st NF, so does that mean I do not check for other greater forms? Also what is the example of schema which is not in 1st NF?
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Challenge: Build MySQL table that's not in first normal form [closed]

I have read numerous books and articles about database design and SQL in which it is said that a database should be in first normal form (1NF). (Some then go on to describe situations in which it may ...