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 for conditional detail table
I have an expense management system for monthly expenses. Expenses are of two types: one-time monthly expenses, and daily expenses for each day of month. I have created the following tables:
...
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2answers
24 views
MySQL Database Normalization Foreign Keys. One to Many relationship. With Diagram
Here is my database design. I've been doing a lot of reading and still don't really know what I'm doing. Hoping you guys had tips!
My DB will have millions of entries.
Many "People" rows will have ...
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3answers
28 views
how to convert a table into second normal form
I am really struggling to convert the table into second normal form
ive tryed examples which are much easier however i can't seem to be able to identify the keys for this one and work my way forward. ...
2
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2answers
48 views
Design consideration regarding state handling: how to store multiple, variable states for one entity
First I have to admit that I'm not a database professional neither are my colleagues. For a new project my colleagues and me came to a design question we couldn't really solve easily. And all the ...
6
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4answers
367 views
How can a database be normalized when an optional field causes denormalization?
Suppose you have a warehouse full of widgets. Each widget in the warehouse is stored in a specific identifiable location within the warehouse. You might have a schema which looks like this:
A ...
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1answer
45 views
How would I change this relational model to fit a nosql database?
Because of things beyond my control, I have to switch from a relational database to MongoDB for the advertising platform I'm helping to build. I've got a relational schema sketched out, but I'm unsure ...
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0answers
47 views
Why is dynamic pivoting not supported?
TL;DR What is the reason that in 2013 we still can't define a VIEW that displays some pivoted data with a dynamic column set.
TL;DR/2 Is pivoting data a denormalization technique?
First: Not going ...
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votes
2answers
149 views
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 ...
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1answer
106 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, ...
1
vote
1answer
90 views
Functional Dependencies and Normal Forms
I'm trying to grasp the concepts of functional dependencies and normal forms, specifically first (1NF), second (2NF), and third (3NF) normal forms. The link here was extremely helpful in deciding the ...
0
votes
3answers
57 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 ...
0
votes
1answer
45 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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1answer
92 views
Record with variable number of columns?
I am trying to model a cable mapping for devices. Each device has multiple cards, and each of those cards has multiple ports. Since both the number of cards and ports vary, I am confused on how to ...
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3answers
81 views
Normalization/normal forms - May a field describe an other field?
Like this:
CREATE TABLE persons(
id serial8 NOT NULL PRIMARY KEY,
name varchar,
-- A lot of other fields
date_of_birth timestamp with time zone,
date_of_birth_precision ...
1
vote
2answers
223 views
Refactoring/normalization - but almost empty table
I normalized a legacy DB into this structure:
But I'm not sure if it is correctly normalized. I don't feel very comfortable with the almost empty filters table.
The requirements
A group contains ...
1
vote
0answers
58 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 ...
7
votes
2answers
164 views
Best relational database structure for this data
I'm in the process of creating a database scheme for the following scenario:
There are users
Users have roles (such as "Developer" or "CEO")
Roles have applications (such as "Topdesk")
Applications ...
1
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1answer
91 views
Approach to Analyzing Database Requirements
When presented with requirements for a database driven system, I always find it useful to imagine a world with no computers, where data records were kept in filing cabinets and data was collected by ...
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3answers
283 views
Simple scenario needs to go from Unnormalized Data to 3NF - Review Please
NOTE: The Question has been updated. View Edit Revisions to view original question.
The scenario. An animal charity that at the moment, track their establishment's costs via a spreadsheet like so:
...
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vote
3answers
132 views
Complex query with multiple normalized fields
We have a fairly simple table structure, but with a LOT of fields per table (talking 40+). This data is initially produced in plain-text, user-readable tables, but then it is translated into ...
1
vote
3answers
224 views
Best practices for history/temporal tables?
Suppose I have an object, with certain fields which I want to track history, and certain fields which I do not want to track history. From a normalization perspective, is the following schema alright:
...
2
votes
1answer
399 views
Normalisation from 1NF to 3NF
I need some guidance on normalisation from 1st Normal Form to 3rd Normal form. I have already set up my database which is working fine but needed to show some normalisation to show that I did do some ...
2
votes
2answers
135 views
Why is this relation in 3NF?
I have a relation:
R4 = {{T,U,V}, {T โ U, U โ T, T โ V}}
I know from looking at the answer key that this relation is in BCNF.
I'm going through the process of rigorously determining what normal ...
0
votes
1answer
85 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 ...
0
votes
1answer
90 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 ...
2
votes
2answers
89 views
How to normalize data based only on the repetitions
Given a non-normalized data table, is there a good a strategy to attempt to normalize based on repeated data? Assume we have no information about the significance of the columns.
In a small example
...
4
votes
3answers
801 views
How to have a one-to-many relationship with a privileged child?
I want to have a one-to-many relationship in which for each parent, one or zero of the children is marked as a โfavorite.โ However, not every parent will have a child. (Think of the parents as ...
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2answers
196 views
History table design for supertype/subtype
I'm designing an asset management database that tracks IT hardware. I decided to use a supertype/subtype design. I'm at a point where I want to track history of changes for devices. I wanted to use a ...
0
votes
2answers
148 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??
2
votes
1answer
119 views
Can I normalize my experimental data table further?
I am attempting to get a MySQL database to 3NF, but I'm unsure as to how to get there. I'm new to database design, so please correct me if my understanding is incorrect.
I have 6 columns: ...
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vote
2answers
152 views
Separate or Combine 2 Tables with Similar Attributes?
I have two kind of users in my business system: Customer and Employee.
Both user have Username, Password, Fullname, Phone Number, Email, and other similar attributes.
I have a difficulty to ...
2
votes
1answer
992 views
Decomposition of a relation to 2NF then to 3NF
I'm currently studying for my exams and the trouble I am having is how to decompose a relation R with given functional dependencies into 2NF then 3NF.
For example for the following R and functional ...
3
votes
1answer
295 views
Normalized Table Structure for Logging
How can I normalize a table that has four columns for logging the latest activity for a single record:
Created On
Created By
Modified On
Modified By
We have dozens of tables, all with these 4 ...
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0answers
71 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?
...
2
votes
1answer
194 views
Splitting a column to normalized table
I have a de-normalized table as
Original De-Normalized Table
id text
23 first,second|third,fourth,fifth|sixth
I want to normalize the database to create the following tables
Table 1: (Split by ...
3
votes
1answer
104 views
I need help to migrate denormalized table content to normalized form- MS Access
I have a staff database where we are storing information in Normalized form. There are 3 entity tables and 2 mapping tables connecting these with m-n relationships
However, for ease of collecting ...
2
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1answer
248 views
What is best practice to organize / normalize database tables?
I manage group that uses a database that is about 12 years old.
There are more than 200 tables / views that have been created by various people over the years, many of them no longer with us.
Most ...
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vote
1answer
157 views
Does my design adhere to 3NF?
I created this schema with OpenOffice.
Does this design adhere to 3NF ?
(A relationship link between Equipment and Supplier_Equipment , Customer and Membership should be created but OpenOffice ...
1
vote
1answer
30 views
Stroring a type of an entry
There is a table estate with numeric fields districtru and districthe (for a name of a district in Russian and Hebrew), which refer to primary keys of the table districts. The districts table has the ...
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1answer
217 views
Are these database tables normalized?
I am developing a webapp for an institute and I designed these tables:
Are these tables normalized?
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votes
1answer
92 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 ...
2
votes
3answers
216 views
First Normal Form, why is it good and how does it reduce redundancy
I asked a similar question on SO and was advised to ask the type of question here. This is for a course on relational databases. A sample problem asks "how come every table in a relational database ...
2
votes
4answers
218 views
Does my table violate normalization rules?
I am developing an emulator for a game. My item table looks like this:
-- ----------------------------
-- Table structure for `items`
-- ----------------------------
DROP TABLE IF EXISTS `items`;
...
1
vote
3answers
172 views
Does this design satisfy 3NF, and can any improvements be made?
Does this design satisfy 3NF, and can any improvements be made?
If it does not satisfy 3NF - why?
By improvements, I only care if it will seriously affect scalability, efficiency, etc - I'm not ...
2
votes
2answers
562 views
Separate archive tables or soft delete for inventory database
I'm building an inventory database that tracks computer equipment and other hardware devices. At some point in any device's life it is retired and gets archived. After it becomes archived it needs to ...
1
vote
2answers
46 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
96 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
90 views
Expanding contractions/number ranges into separate records [closed]
I am planning the migration of a directory of image files plus a FileMaker-database containing the corresponding metadata into an Imagic IMS database (formerly known as ImageAccess). The vendor ...
6
votes
4answers
1k views
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, ...
4
votes
1answer
193 views
MySQL database normalization 3NF
I have homework where I need to create simple web interface and a DB normalized to 3NF. I've chosen ISP client selfcare as my database purpose. Web interface is no problem, the normalized DB is. After ...
