Questions tagged [normalization]
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.
642
questions
0
votes
1
answer
26
views
Set into multiple rows [duplicate]
I have the following data
SQL> SELECT id, relatedIdInASet from tab;
+----+------------------+
| id | relatedIdInASet |
+----+------------------+
| 1 | [12,34,56] |
| 2 | [11,12,22,34] |...
- 437
1
vote
1
answer
29
views
A clarification about data normalization
I've been a software developer for 8+ years now and I think I have a pretty good grasp of the concepts but as an entirely self-taught developer, I have some unfortunate gaps in proper terminology. ...
- 111
0
votes
0
answers
16
views
Correctly handling multi-preferences updates in SQL
I have a Postgres schema as (simplified):
A user can have n number of car preferences.
users_table
------------
id auto_increment int (PK)
name text
cars_table
-------------
id auto_increment int (PK)...
- 101
0
votes
0
answers
33
views
Design proper schema for flexible entity field
I have some entities modeled like on the picture.
Every entity have field classifications which contains list of Classification.
Classification itself can have any name and value, all represented as ...
- 101
0
votes
1
answer
97
views
Normalizing an old database
I have a need to normalize an old PostgreSQL database, and I have an idea on how to do it which I would like to hear your opinions about.
The aspect that needs to be fixed is this:
We have a consumer ...
- 101
-1
votes
2
answers
101
views
How to design to avoid duplicate Foreign keys
I wasn't really sure how to title this question. I have three tables User, Photo and Album. A user has many Photo objects and many Album objects. However, after a User has added a given photo they may ...
- 101
0
votes
1
answer
101
views
Is there a dependency preserving, lossless BCNF decomposition for this relational schema?
R(A,B,C) where {AB -> C , C -> A}. The candidate keys are {A,B} and {C,B}. This is in 3NF but not BCNF because of {C->A} . Now it seems like this can't even be split into a lossless BCNF, let ...
- 107
-2
votes
1
answer
111
views
Normalize to 1NF and 2NF, also 3NF (if possible)
I have a sample table with the dataset unnormalized, So I need to make it normalize in 1NF and 2NF and answer 5 different questions from those tables.
Part of my dataset: (unnormalized)
category |item ...
- 97
1
vote
2
answers
79
views
Separate table to store long string identifiers
In my postgres DB, have an assets and a sales table. The current owner of an asset is identified by an Ethereum address with 42 characters, e.g. 0x81238432CE9b51Fbc2b59AFD74Ba8D09863B8B00. A sale has ...
- 111
1
vote
1
answer
19
views
How to model data which sometimes (but not always) has a subsection?
I'm trying to help my wife create a schema for a project of hers, and I'm somewhat stumped by some of her data and how to model it.
She has a bunch of "standards" that go in to a database. ...
- 13
1
vote
1
answer
153
views
Should a counter column with frequent update be stored in a separate table?
I have a MySQL/MariaDB database where posts are stored. Each post has some statistical counters such as the number of times the post has been viewed for the current day, the total number of views, ...
- 23
1
vote
2
answers
358
views
Create an index for fields within an array of composite type
My question is a follow-up to the question answered here:
https://stackoverflow.com/a/15041094/994263
Considering a table with an array column of a composite type, is it possible with PostgreSQL to ...
- 113
-1
votes
1
answer
18
views
Table normalization of given table
I've got a table and I'm supposed to figure out why it breaks with 1NF, 2NF and/or 3NF.
I know the differences between these three, but I'm bad at telling what attributes are primary keys and what is ...
- 11
2
votes
1
answer
58
views
How to enforce UNIQUE constraint for sixth normal form in PostgreSQL
I have a table person which I am planing to normalize to the sixth normal form.
The table has attributes username, email, and phone. The reason I want to go to the sixth normal form is keeping the ...
2
votes
0
answers
43
views
How to enforce NOT NULL for sixth normal form in PostgreSQL
I have a table person which I am planing to normalize to the sixth normal form.
The table has attributes username, email, and phone. The reason I want to go to the sixth normal form is keeping the ...
0
votes
1
answer
92
views
Does combining multiple tables into one table with more than 100 columns improve performance and overall design?
I have 10 tables without any type of foreign key relations between them. All the tables have the same primary key. In this case, "stock_id" is the primary key. All table columns describe a ...
-1
votes
1
answer
116
views
How to query likes and user details for posts?
I'm pretty new to the world of databases and SQL.
I'm trying to build a system for users to submit posts and like posts. I've been looking at a few similar questions on this site, reading about third ...
- 101
0
votes
1
answer
331
views
Strong vs weak entity types on SQL
I have a 3NF normalized database design and was trying to understand the concept of strong vs weak entity types and my understanding is weak entity types are tables that don't have a primary key. ...
- 21
1
vote
1
answer
101
views
normalisation in DBMS
For the relation schema R(A, B, C, D, E) with the following FDs
FD1: {A,B,C} → {D,E}
FD2: {B,C,D} → {A,E}
FD3: {C} → {D}
I Decomposed R into a set of BCNF relations.
I got candidate keys as {A,B,C},...
- 21
-1
votes
1
answer
104
views
Normalisation from 2nf to bcnf
This is a question from a textbook
Consider the Relation R={A, B, C, D, E, F, G, H } and the set of functional dependencies.
A→C B→CG AD→EH C→DF A→H
What is the key for R? Decompose R into 2NF, 3NF ...
- 3
0
votes
1
answer
122
views
How to create a trigger that generate a random specific output to insert into a table in MariaDB?
I have an account table which is laid out in 3NF:
CREATE TABLE account (
account_id INT AUTO_INCREMENT,
customer_id INT NOT NULL,
account_type_id VARCHAR(15) NOT NULL,
is_active ...
- 13
-1
votes
1
answer
89
views
How can I prove / disprove If A ↠ B then AC ↠ B
If A ↠ B then AC ↠ B is it true or false and if so can have example why?
- 1
0
votes
1
answer
46
views
Finding a balance with normalization and when to keep similar data together
I'm integrating with services that use OAuth, and the data I need to save to the database is very similar. However, there are slight differences with the first two implementations.
They both have a ...
- 437
0
votes
1
answer
1k
views
Unnest array values from multiple columns with dynamic unpivot
I have been given several tables in wide form that I would like to convert to long form. Unfortunately, they have about 60 columns.
Example input:
CREATE TABLE tbl_wide (
p_key integer PRIMARY KEY,...
- 1
2
votes
1
answer
57
views
Is there an agreed upon definition of 1NF and 2NF? [closed]
I am trying to understand 1st and 2nd normal forms and I see lots of seemingly conflicting information, or just different sets of requirements which leaves me confused. I have a table that I want to ...
- 123
0
votes
0
answers
189
views
Move address data into separate table
Currently address information is stored directly in the OrderHeader and Customer tables. I would like to create a separate Address table and replace the current address information with a reference ...
- 1
8
votes
2
answers
926
views
Should stored financial transactions include some data redundancy?
I am currently storing financial transactions in the following table (shortened for brevity):
id INT
start DATETIME
end DATETIME
rate INT
usage INT
usage_fee INT
amount INT
commission_pct INT
payout ...
- 185
1
vote
1
answer
193
views
Database architecture of high frequency sensor values
I have a lot of sensors (around 1000) and want to save their values. The sensors
will mostly work around a sampling rate of 10Hz.
Regular queries will be used for a live-view application. It can be ...
0
votes
0
answers
132
views
Is there a commonly accepted definition of 0NF?
The normal forms from 1NF and upwards have well known definitions in papers by Codd and others.
I have sometimes seen the term 0NF or zeroth normal form used for a data set which is not in first ...
- 121
1
vote
0
answers
335
views
How to design a relational database schema for music recordings?
I would like to design a simple relational database schema for music recordings and normalize it to the ultimate normal form with respect to the projection and join relational operators, which is ...
- 71
0
votes
1
answer
45
views
How can I improve this normalization to 3NF/How do you self-check normalization?
this is NOT homework, I'm just trying to improve my normalization skills. The first part is the functional dependencies i've identified and the second is what I believe the appropriate 3NF ...
16
votes
3
answers
3k
views
What is the reason to "normalize your databases"?
In the past, I've been told (on this site) that I should normalize the values in the database - using a lookup table instead of using direct (string) keys.
I am confused why this is so good that ...
- 421
0
votes
1
answer
84
views
Does unique email in user table violate normal forms?
USER(userID, email, name, address, ...)
userID
primary key
incrementing bigint
email
unique identifier
can be modified by user
To me this seemed like a good idea, but then I started to wonder: ...
- 9
0
votes
2
answers
158
views
How to "normalize" external data before insertion into "Data Warehouse" like database?
I want to be database agnostic but let's say we're inserting data into SQL Server which is to be used as a data warehouse.
There are MILLIONS of email records from an email platform that wasn't too ...
- 1,503
-1
votes
1
answer
587
views
Advantages and disadvantages of normalisation
Briefly, what are the main advantages and disadvantages of normalisation as a technique for database design?
It may be easier to answer this with a snapshot of some unorganised data, as a concrete ...
- 27
0
votes
1
answer
37
views
table organization with data that will never change
for reference, almost all my DB experience is with mongodb and this is my first postgres project.
I'm storing data updates from decentralized finance crypto pools.
The data structure I'm exploring is ...
- 217
0
votes
1
answer
525
views
How do I identify functional dependencies and normalize a table based on the attributes?
I'm having trouble identifying the combination of attributes which make up Functional Dependencies(FDs) of a particular table. While I understand how Normalization process works when given the FDs, I'...
- 13
1
vote
3
answers
277
views
Does relational design discourage splitting tables unnecessarily?
It's been a long time since I studied relational design, but I had a vague memory that it encourages not splitting a table unnecessarily. For instance, given the functional dependencies
K -> A
K -&...
- 152
0
votes
2
answers
1k
views
How to normalize a table with multiple cells that have multiple values?
So I'm doing a task where I take a massive list (30,000+) of movies on Wikipedia that have multiple columns (such as the films name, the genre, the cast, the plot etc.) and upload it into ...
- 13
1
vote
3
answers
155
views
Is it allowed to for two tables to have two types of relationships between them? [duplicate]
I have been going back and forth working with relational and no-sql databases for some time now and my questions may be the result of mixing the way of thinking about how to approach a problem.
So ...
- 119
-1
votes
2
answers
781
views
SQL: shopping cart design for a multi vendor marketplace [closed]
I'm working on a B2B marketplace where users can order from different suppliers/vendors. The following image is a sample from my original schema to clarify the cart functionality.
The cart_item table ...
- 27
0
votes
2
answers
52
views
Is it possible to store historical configuration settings for each row of data without cramming all the configuration settings into each row of data?
For background: I was recently hired as a database engineer for a water treatment company. We deploy water treatment machines to sites across the country, and the machines treat water and send ...
0
votes
1
answer
36
views
Normalization using DENSE_RANK and LAST_INSERT_ID
db-fiddle
I have created a table called orders (orderId, customersId) and a table called orderDetails (orderId, productId). My goal is to denormalize a table called temp which is like
scanId, ...
- 163
-1
votes
1
answer
285
views
How do I prove this relation is in the `3FN`?
Consider the relation R(A,B,C,D,E) and the set of functional dependencies F={A->D,D->C,BC->AE}
I need to prove this relation is in the 3FN, however I don't think it is; in fact, I don't even ...
- 101
0
votes
2
answers
477
views
MySQL Insert Values Into Normalized Relational Database (multiple tables) at the same time
I have normalised my database to 4NF. How do I now insert values at the same time when records have been split into multiple tables? most of the child tables reference their parent table CUSTOMER ...
- 21
-1
votes
1
answer
36
views
If `AB->C` and `A->B` , `A->C`?
I'm new to databases, is this true? if so, how can we deduce that?
I don't know how to use the properties to get an answer, could you help>
1
vote
3
answers
542
views
How can I design Person table in MySQL?
I have two person type: Users and Clients.
Users can login the panel but clients can't login the panel.
My current database: (but this design not good for me. I need to connect these tables to the ...
- 21
-1
votes
2
answers
47
views
Is this the proper way to integrate normalization? [closed]
I'm trying to wrap my head around normalization.
Is this the proper way to create a database with this data? How much more effective is it to use a foreign key instead of just repeating AAPL for ...
- 103
-1
votes
1
answer
1k
views
How can I design address table?
Hello I need designing addresses table. I designed it but I didn't like it very much.
My needs:
I have customers and users (admins). I have addresses for customers and users. We need design in ...
- 21
0
votes
1
answer
178
views
How can I design Address table with different types?
I have a Address table and different address types like Personal and Corporate. I design a table but I think is breaking normalization rules. How can I improve this design?
My design:
- 21