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.
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Table normalisation and empty values
Here are two ways I can optimise mapping of a text field with several other attributes to question and answer. First approach is, creating a map table with both question_id and answer_id in which ...
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1answer
25 views
Refactoring out a boolean column [closed]
I have a Pets table (cats, dogs, you name it) with over a million records. For simplicity sake, it looks like the following:
Pets
Field Type Null Key
id int(11) NO ...
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0answers
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Are derived attributes transitive dependencies? [closed]
So I was drawing a dependency diagram for a table and this point striked me if derived attributes are transitive dependency?
Image
Here, is TOTAL_AMT in a transitive dependency? Or is the table in 3NF ...
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19 views
Function dependency NF1,NF2,NF3 [closed]
I'm not sure if the function dependency process is correct or not, and would like to help verify the function dependency from normalization. NF1, NF2, NF3
Relational Schema
function dependency NF1
...
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1answer
57 views
How to decompose R(a,b) with non FDs?
Assume student table R(a,b,c) is R(Student#,Sname,Class)
Student#(PK) | Sname | Class(PK)
001 danny c1
002 angie c2
002 angie c3
003 philip c1
...
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1answer
37 views
Database Normalization Advice [closed]
I have database for multi store application. So, I have 3 type of user thats Admin, Customer, Merchant and I have 3 table for users. User table, Customer table, Merchant table.
User Table;
id
...
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1answer
23 views
Weak Entities + Partial Keys + 2NF [closed]
I'm a bit confused on the concept of weak entities and normalization and couldn't find any answers online. I know that generally weak entities have a partial key to uniquely identify its own records ...
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1answer
25 views
Celebrities database with multiple parent categories and children categories? [duplicate]
I am creating a React/Laravel web application that will allow the user to search and navigate through celebrities based on their 'categories'. I have set up a Categories table using MySQL like so:
*...
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1answer
18 views
Where can I get a proper dataset for performing Normalization techniques? [closed]
I'm new to databases and I just started with learning different techniques of Data Warehousing. I was given an assignment to perform Normalization techniques on a dataset of at least 1000 rows with ...
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1answer
23 views
Is it correct way having status or Summary columns in parent table or should choose another precedure?
My Parent Table is "Jobs" table, and there is child table that records Job's actions named "JobActions" as below:
Jobs (JobId, JobType, CurrentStage, AssignedTo)
JobActions (JobActionId, JobId, ...
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1answer
81 views
Need Help With BCNF Decomposition Problem
I'll try and keep it as quick and concise as I can: I'm currently a novice developer who's super eager to learn Database Normalization and Optimization so I can up my skill in Full-Stack development, ...
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2answers
29 views
Relationship normalization in SQL Server
I want to know should I remove PersonTypeId from Persons table or is it a good idea to have it in there?
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2answers
253 views
Alternatives to storing a record with exactly n multiple foreign keys from the same foreign table, where the relationships can't be repeated
Say there are entities called singulars, and entities called relationships.
It takes exactly two singulars to make up a relationships entity.
That pair of singulars can't be repeated elsewhere in ...
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0answers
35 views
Can there exist Tables with no Non-Prime Attributes? If so, are they always normalised to 3NF?
Can there exist a table with no non-prime attributes?
Here is an example of a table which I believe has no non-prime attributes:
I came to this conclusion because the list of attributes in the ...
1
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1answer
71 views
Does one of the normal forms require separation of repeating clusters of values into another table?
Should the repeating values in the "Sales" table below be separated out into a second table as part of the process of database normalization? Note that none of the values are functionally dependent on ...
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2answers
36 views
Normalization Excercise Clarification
Have a bit of confusion regarding a normalization from 1NF to BCNF. The teacher gave us this excercise to illustrate a normalisation all the way up to BCNF. I think I have found a problem with the ...
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1answer
57 views
Database Design: Normalization and NULL values
I have normalized my table from 0NF to 2NF (hopefully correct).
How do I now go from 2NF to 3NF?
Also, ResponseToTransactionId is a recursive foreign key that will contain NULL values a lot of the ...
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0answers
31 views
SKU and Price on product that have multiple attributes
Currently, my Inventory system is writing products data like this:
T-Shirt Gildan -> blue, L, short -> stock: 140 -> price: $40
T-Shirt Gildan -> blue, XL, short -> stock: 0 -> price: $45
T-Shirt ...
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1answer
49 views
How to normalize a lookup table containing NULL? - or should I bother?
I have a table fee listing different fee descriptions and another table fee_amount holding the amount of the fee. The fee amount is different for each year, whether it's a joint fee or not and what ...
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1answer
91 views
BCNF decomposition step without functional dependencies
I am performing the BCNF decomposition for the relation R = (A, B, C, D, E), that has the set of functional dependencies AB -> C, CD -> A, C -> E, and C -> B.
After checking that the ...
2
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0answers
42 views
How to handle / model “cost of provided spare parts per PO line item” where one spare qty is divided between multiple line items? / Postgres 11
Problem
My objective is to help improve the data modeling / handling of my companyās present cost-of-goods [āCOGSā] calculation.
Everything in the current Postgres 11 table structure is pretty ...
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1answer
47 views
How to normalize a database which uses tables as references to other tables?
I'm trying to create the database for my application, but I cannot manage to normalize my data on a MySQL database.
I have a Types of map entity
The Types must have one or more Models associated to ...
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1answer
37 views
Database design - logging of same value when recorded in multiple tables
I need to record changes to a particular value, which is read as part of multiple events that are all separately tracked, and be able to view a log of all of the values later.
I think an example will ...
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0answers
28 views
Schema design for an entity with 'heterogeneous' status types
Consider a notification system which gets some event data and list of business email addresses as input (the list is basically computed by looking at which users/addresses are subscribed to which type ...
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4answers
90 views
Trouble deciding what/how many tables to use; normalisation suggests one
More of a conceptual question for the community, as I am not "thinking with databases" as much as I would like to just yet. I am using Oracle Database 18c Express Edition with SQL Developer.
I have ...
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1answer
224 views
Store timeseries data in normal SQL database
I have got historic data of around 20 machine sensors with a time resolution of one second stored in csv-files which need to be imported to a SQL database prior to further data handling and analysis.
...
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0answers
11 views
What normal form is table with two self-determining attributes?
I have table with these attributes:
employee_id (PK)
[...other non-important attributes...]
user_account_id
There are 2 functional dependecies:
employee_id -> user_account_id
user_account_id -&...
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votes
1answer
20 views
Structure to represent matches between teams or individuals
Say there's a sport that can either be contested between two individuals, or two teams comprised of several individuals. So obviously we need the standard players, teams and teams_players tables. But ...
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0answers
27 views
Normalization of a Database - Is primary key = candidate key?
I'm given a database called Projects where I know that id, pid, sid is the primary key. My goal is to decompose this database such that each sub-relation is in BCNF or 3NF.
P(id,pid,sid,sn,pn,mid,mn)
...
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1answer
59 views
how to professionally normalize my database - screenshots included
Hello database administrators.
I got some excel spreadsheet with data of "my customers" and I'd like to create professionally designed database out of it.
Can anyone tell me how this data should be ...
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1answer
23 views
One to many relationship for constant data
I am saving a book inside a database, so that it can be properly queried. The book I'm working with has constant data. Not a character of it will be changed in the future in any way, once the book has ...
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1answer
45 views
Removing duplicates (deduplifying) from an existing, huge, table
I have a huge table. Each row has an ID, some columns which relate to that ID specifically, a short (DNA) Sequence, and some columns which relate to that sequence particularly. If these have not yet ...
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4answers
304 views
Why is it considered that a set unnormalizes a database absolutely?
In order for a relationship to be on 1NF it needs to have all values as atomic, if there's a set it's not even in that first normal form:
But intuitively I think that a table with that set would be ...
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1answer
77 views
I need to put the data from the diagram in 3NF [closed]
This is a simple list table of a company trying to keep track of employee assignment to company projects (in other words, not a database but a flat one table file).
You will design a database for ...
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0answers
84 views
Are these tables in 3NF? [closed]
Update: I updated the question to be more specific and also updated the diagram.
I am currently in my last semester, I did use SQL before then I left for MongoDB but the practice project requires to ...
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0answers
27 views
SQLServer: Storing File Extension and normalization?
After much research, I've decided to store pdf/img/txt/doc/etc files on a web server instead of a database. However, the reference to that file will be stored in SQL Server.
So far I have...
| ...
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1answer
36 views
3NF for table layout [closed]
Assuming a table with the following columns
UserID, UserName, Console, GameID,
GameTitle, GameVendor, VendorCountry, Game Genre, NumberOfPlayers
Is this the correct 3NF?
Users(UserID,UserName, ...
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1answer
34 views
Database Model for Various Type of Sensors
I am planning to build a database that will store sensor value for various type of sensors in a factory building. Is there any best practice on how to do this?
-
Option 1 : should I integrate all ...
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1answer
112 views
Normalization of the this relation just want to know what are the functional dependencies
Consider the Customer account database of the ABC big bank, which keeps data for customers and their orders. A database of only one relation is designed, as shown below:
ABC(
customerNo,
...
2
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1answer
78 views
Why is this relation not in Boyce-Codd Normal Form (BCNF)?
I have the relation (A,B,C,D,E).
The relevant functional dependencies are:
{ E,B,C } ā { D }
{ A,B } ā { C }
{ E,B,D } ā { C }
{ E,A,B } ā { D }
The candidate key is (E,A,B).
I do not understand ...
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1answer
169 views
Finding all possible minimal covers
I have a relation schema R = {A, B, C} and the following functional dependencies:
A ā B
A ā C
B ā A
B ā C
C ā A
C ā B
How many different minimal covers can I derive from this relation schema? I have ...
8
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6answers
2k views
Does an excessive table violate normalization rules?
Here is an example of some tables that exist in a database where I work. The data isn't actually around schools, but the structure is identical.
There are four tables:
** School **
School Id, School ...
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votes
1answer
36 views
How do I bring a relation/table to first normal form (1NF) when one of the attributes/columns can hold any number of values?
For example,
MOVIES (movieid, movietitle)
where movietitle can be any number of words, so I believe it's not atomic.
How do you bring something like that to 1NF?
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1answer
81 views
Is this table really in first normal form (1NF)?
Does this table comply with 1NF, even if CourseNo and StudentNo?
Student(StudentNo, StudentName, Major, CourseNo, CourseName,
InstructorNo, InstructorName, InstructorLocation, Grade)
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1answer
74 views
Attempting to identify minimal functional dependencies in a Compact Disc details scenario
I believe this relation/table is in first normal form (1NF):
Collection (cd_id, title, label, artist, type, country, song_id, song_title, length)
Note: Bold means keys.
What I have managed to ...
4
votes
1answer
62 views
Attempt to decompose up to second normal form (2NF) in a scenario about students and courses
1NF:
(student_id, name, start, program, course_code, course_name, faculty, credits, time, grade)
Minimal functional dependencies (identified):
{student_id} ā { name, start, program }
{course_code}...
2
votes
1answer
39 views
How can I normalize this schema about students and courses further?
1NF:
I am working on 2NF:
student (student_id, name, start, program)
course (coure_code, course_name, faculty, credits, time)
student_course(student_id, course_code, grade)
I am trying to achieve ...
3
votes
1answer
141 views
Normalization with two potential primary keys
I have the following STUDENT relation in first normal form, where id has been identified as the primary key (email here is also unique for all tuples):
STUDENT(id, email, first_name, last_name)
I ...
2
votes
0answers
49 views
Design issue in transitive dependencies between tables
This is a made-up scenario, but I imagine that it can be of general interest, so I'll post it here. Imagine the following business rule:
A course has a grade scale that determines what grades a ...
4
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2answers
120 views
Does a computed column break 3NF (third normal form)?
From my understanding of 3NF, there should not be any transitive dependency.
However, this is what I found from the AdventureWorks2012 database Production.WorkOrder table. Since StockedQty is ...
