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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Database normalization for sensor data
I'm working on the backend of a quality evaluation tool. And I hit a the limit of too many columns.
SQLSTATE[HY000]: General error: 1005 Can't create table xxx.xxx (errno: 185 "Too many columns&...
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How do I ensure I have split my tables without loss of data?
This is w.r.t Database Normalisation, when I have a redundant table that causes anomalies, I would want to consider splitting it in smaller tables as per the NF rules.
BUT
Say I split a big table into ...
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Meaning of “Dependency” in Relation to Elementary DB Normalization
In trying to figure out why the following table definitions from a textbook exercise about nurses in hospital wards is not in 2NF:
Ward (WName, Location, WType)
Ward-Nurse (WName(fk), NurseID, ...
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1answer
41 views
JSON vs Record/Struct type in a DB
It seems like some databases have implement a Record/Struct type and others have implemented a Json/Jsonb type to handle nested data structures. A few examples being:
BigQuery Struct
CockroachDB ...
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1answer
40 views
database design - table with multiple nullable foreign keys
Context:
I have 3 unrelated entities (tables) Entity1, Entity2 and Entity3
I have a table called Operation, which can have multiple targets.
A target for an operation can be Entity1, Entity2 or ...
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How can a 'Request' store a 'Result' code and its associated 'Error' code and still enforce the relationship between Result and Error?
I'm an application developer creating the database structure to represent a flat file message format. I'd like to ask the collective knowledge the best/correct way to represent the following scenario:...
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2answers
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Postgres normalize human name string
Is there some function to normalize name string:
select normalize('R.C. Bray')
'R. C. Bray'
Or the opposite direction?
The simple replace('. ', '.') or replace('.', '. ') is wrong and may be ...
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1answer
23 views
More tables or More records performance wise
i am into a scenario that upon looking at the our project database contains Identical tables with the schema described below:
id
url
region_1
region_2
region_3
region_4
date_created
My ...
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Is this definition of 5NF right?
From what I've gathered from my textbook, 5NF doesn't allow lossy decomposition, so that when we join tables that are in 5NF, no spurious tuples are generated.
The definition in my book states that:
&...
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1answer
37 views
Most efficient table structure for multi-tenant database
I have a conventional relational database (mySQL) with several entities stored in their own table. Three examples are images, events and organisations.
We are making a change to the way our site works ...
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Can a table be un-normalizable or am I misunderstanding the theory
I was considering normalizing a flat table (SQLite if its relevant) I'd been working with in a small personal project and it just didn't seem to make sense.
Consider an example table like below. Each ...
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1answer
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Relational-JSON overlapping with association [closed]
I have a composed class called sensor that is linked to a main class Node such that:
class node is linked with another node to make a communication that produce an event
class sensor can as well ...
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3answers
37 views
Is storing data that can be inferred go against data normalization?
To simplify lets say I have two tables PROJECTS and JOBS. A user creates a project and runs 1 or more jobs using a project.
So it would possible look something like this:
PROJECTS
[PK] project_id
...
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1answer
40 views
How do foreign keys affect partial and transitive dependencies (databases)
I'm struggling to work out how foreign keys can affect partial and transitive dependencies when normalising databases.
I have multiple tables, two of which are job offer and accepted job.
in job offer,...
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1answer
38 views
Table normalisation and empty values [duplicate]
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
26 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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1answer
41 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
52 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
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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
21 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
24 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
92 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
261 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
54 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 ...
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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
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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
81 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
35 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
57 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
127 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 ...
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0answers
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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 company’s present cost-of-goods [‘COGS’] calculation.
Everything in the current Postgres 11 table structure is pretty ...
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1answer
48 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
39 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
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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
384 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
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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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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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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
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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
24 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
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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
313 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
128 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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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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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
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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
41 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,
...
