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Questions tagged [denormalization]

Database denormalization is the action of adding redundant data to database for performance optimization. This is the opposite to normalization where data is split into separate tables.

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Does any MariaDB engine have the option to declaratively or configuratively abstract highly-redundant data?

I have an application which is architected in a "NoSQL" style around one fully denormalized "main table" which currently just holds a primary key and one JSON-valued column. For reasons which are ...
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How to denormalize many-to-many relation without nested select?

I have the following schema: house has many students, student has one house gender has many students, student has one gender game has many students. student has many games For instance, consider ...
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133 views

Why is data integrity not possible when using denormalization?

This tutorial says the following: For proponents of denormalization, the thinking is as follows: normalization creates more tables as you proceed towards higher normal forms, but more tables ...
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Table with only one column because of many-to-many relationship?

Right now I have three tables: person, alias, and person_alias. As suggested by the names of tables, one person can have multiple aliases and one alias can be used by many people, and hence I add a ...
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Are updates the only disadvantage of denormalization?

I am trying to understand what are the disadvantages of denormalization. Say that I have the following database (School_has_Student is a denormalized table): I have read that the problems that you ...
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272 views

Select records based on earliest date in a linked record

I am a retired teacher working on my first MYSQL database as a personal project; please let me know if I've inadvertently violated conventions. And thank you! The database's domain is fiction stories,...
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78 views

Is this a good database design or transition? Normalize to Denormalized for Data Warehousing [closed]

As of now in sql server , we have a data and a series normalized table structure that is connected to a C# web app (Human Resource / Recruiting System) (slightly medium (or small 12,000 rows.) size ...
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2answers
89 views

Modeling Sellers and Products

I'm trying to model product and seller information. The seller can be either an individual, or a company, or a company with branches (and the product is being sold by a particular branch). Each ...
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2answers
63 views

Normalizing the Test Table

I'm a web developer looking to leverage more of the power of my RDBMS. I'm currently learning about normalization of data and database design. In the book that I am reading, we started off with one ...
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2answers
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Normalizing data past initial db design phase

I wanted to poke at everyones brain to better understand when it makes sense to normalize a table that carries redundant data. I recently worked on a project at my startup and really question myself ...
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6answers
2k views

Storing personal data on an invoice to preserve data integrity

I want to store invoice data like addresses of people. But the problem is addresses can change over time - for example someone will move out and change his address. The problem of storing such data ...
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3answers
173 views

When is it beneficial to move duplicate data to a reference table?

If there is column with values from some finite set S, for example S = { alive, dead, unknown } for a life_state column in a persons table, when is it beneficial to add a reference table? Options: ...
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Schema For “Other - Add Comment”

Many user forms contain an option for "Other - Add Comment" where the user can provide an item not found in the given list. In other words, the developer sets the list of items. The user must either ...
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1answer
132 views

Checking if a transitive key dependency is in 3rd normal form

I'm currently trouble determining if one of my schemas is in third normal form. I have a table with columns image_id (A), upload_time (B), uploader_id (C), and image_file (D). A is a key (unique ...
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3answers
184 views

Storing Procedure Fields That Were Used

I am creating a database for production work (specifically lab testing). Most Work is for production, therefore performed strictly according to the Procedure for that Product. By itself, this is ...
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0answers
108 views

Normalization of database according to the given data

I'm creating new database based on existing database, performing some normalization. Here is the table containing multiple information, it's basically for booking trips etc I've divided all the info ...
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2answers
181 views

How to design database tables using normalization in better manner in SQL?

I have designed my tables in below manner. Countries Table:- PkId --- + Country Name --- + StatusFlag 1 | India | L 2 | China | L 3 | Sri Lanka | L ...
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2answers
170 views

Is combining independent tables called normalisation?

So, at workplace, we currently store our audit logs in different tables, depending on what it is e.g. login/access info, configuration changes, etc. These are all independent data with no foreign ...
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2answers
223 views

How can I optimize this query over this logging table?

I am trying to optimize a table layout for a table that logs events. The log table contains three relevant columns: Timestamp, ItemId, LocationId Each row means that at a given time, a certain item ...
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1answer
83 views

Is this really in 3nf?

I cannot comment on https://stackoverflow.com/questions/8437957/difference-between-3nf-and-bcnf-in-simple-terms-must-be-able-to-explain-to-an-8, so I have to post my question here. It is about the ...
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1answer
103 views

Redundant FK on parent relationship is denormalization?

Let's say I have this database client | id | status | sale | id | client_id | date | sale_item | id | sale_id | *client_id* | The *client_id* column is redundant, because we can JOIN and get ...
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2answers
124 views

Two primary keys but not a composite, what is this sort of relationship called?

I am integrating employee/position data with another system. The first system is HR. It has an Employee table and a Positions table. The second system tracks office space and tracks who the office ...
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1answer
652 views

PostgreSQL multidimensional array - ok to use or misdesign in this case?

I have a table called listings. For each listing, the user can upload 5 images. In the table listings, I have a multidimensional array images text[][]. Each multidimensional element will hold [ a ...
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1answer
70 views

ALTER TABLE online by keeping data as BLOBs

Could you please explain me how extreme de-normalization (store the value as a serialized blob will help to ALTER TABLE online? source Additionally, it's crucial to be able to change the schema: ...
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1answer
107 views

Database normalization vs several dozen joins [closed]

Using PostgreSQL I have a few tables that are about 22,000 records and about 275 columns. These tables are actually reports. There are about 25 sections in each report containing anywhere from 4-12 ...
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1answer
102 views

Duplicate data or Relationships?

Given two tables: Product int id int operator_id string name string description int price Operator int id string logo_path string tos_path int tax_number I need to call multiple ...
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1answer
63 views

Similar data with fields redundant in one table

I need four different plans to be stored in one or more tables. All four plans share the fields however some plans have extra fields. All plans fit into the plans-table: PLANS(id, provider_id, ...
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0answers
356 views

Normalization vs denormalization for these kind of data?

I'm using Firebase realtime database (NoSQL), And trying to figure out the best database design for my data. My data is primarily about discounts, each affiliator introduces a number of discount ...
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3answers
796 views

Integrity constraints in a relational database - should we overlook them?

I’m in a permanent discussion with the developers of the company where I work because they say it is better to get rid of relationship enforcement (via FOREIGN KEY constraint definitions) in a ...
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1answer
285 views

Do I have to (sometimes) sacrifice normalization for data integrity?

I often come up against the following challenge, and end up de-normalizing my table design in order to enforce data integrity. I would be interested to hear if there is a different way of modelling ...
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1answer
430 views

How to prevent Performance issue & going for Denormalization

We are planning to do an e-commerce shopping site with PHP-MYSQL combination. I read in almost every link related to Normalization & Denormalization : Normalize until it hurts, denormalize until ...
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1answer
107 views

Complicated database design

We have a situation in a database design in our company. We are trying to figure out the best way to design the database to store transactional data. I need expert’s advice on the best relational ...
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1answer
3k views

Designing a database for a video game business domain with multiple many-to-many relationships

I am relatively new to database design, and I decided to make my own hypothetical database for practice. However, I am having trouble modeling and normalizing it, as I esteem that there are numerous ...
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180 views

Checking for BCNF in a relational database through FDs?

Okay so I know that for BCNF, when listing all non-trivial FD's that everything to the left has to be a candidate key. So I have this relation: Person(Id, TFN, Name, Phone) Where Id and TFN(Like ...
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582 views

Need advice on database normalization

I am working on a basic blood bank database on Oracle. I would like to create a completely basic normalized table and then I will add more details to it. I have done it to the 2NF and I will further ...
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2answers
145 views

Is it a good approach to duplicate data in a database?

I have a program that needs to store traceroutes (among other data). Here is a diagram that depicts the business scenario: My use case right now is to store the traceroutes using the following ...
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1answer
219 views

contradiction of 3rd normal form on address table

I have an Address table and its columns are address_id, address_1, address_2, city, state, country, pin code .Its primary key is address_id . According to 3rd normal form no non-key attribute should ...
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4answers
669 views

Should I Denormalize Tables To Avoid Joins?

I'm in the process of developing a web application, and need some help with some basic db design. Currently, I am unsure of the following three tables: ### User ### - Id - DetailId - etc... (...
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2answers
109 views

should I denormalize for user profiles?

Assuming the choice is to stay with relational model, how are tables structured in the case of large User profiles? All the examples I see consider only simple cases, such as a "profile" containing ...
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6answers
16k views

Possible benefits of storing multiple values in one field of one row instead of as separate rows

During our last weekly meeting, a person that has no background experience in Database Administration brought up this question: "Would there be a scenario that justifies storing data in-line (...
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1answer
1k views

How can I prove / disprove If A ↠ BC and A → B then A → C

/ From GATE 2007 IT: Consider the following implications relating to functional and multi valued dependencies given below, which may or may not be correct. A) If A ↠ B and A ↠ C then A → BC B) ...
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1answer
581 views

Is splitting a CSV column into a separate table (enforcing 1NF) unnecessary complication?

I had very carefully asked the table designer why he had chosen to create CSV columns in multiple tables. The designer's answer was that splitting CSV columns into separate tables was "...
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1answer
1k views

Normalization from UNF to 3NF

I keep getting confused trying to normalize this data. A company makes and sells a product online. There are ten types of Products, each having a code and price. Their Sales Order department takes ...
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0answers
57 views

Is there any literature on “re-normalisation” of denormalised data?

I'm involved in a project, the core of which might be generously described as "re-normalisation" of denormalised data. (To be fair, the initial implementation took only the first 90% of the time ...
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1answer
94 views

Should I split my tables into different tables when all of the data is dependant on the primary key?

For my assignment I have to make a database for my licensing application. I have 12 columns and one column is for the license key. All other columns are data that is related to the license key. The ...
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5answers
6k views

Normalization for postal addresses in US (address, county, city, state, zipcode)?

I've been trying to understand for the last few years which way is good for storing addresses. I've been getting "normalize all the way" but also "denormalize as much as you can" and I just cannot get ...
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196 views

Database sharding, denormalization and synchronization

In sharding, it is advisable to follow a share nothing, shard everything approach. Essentially, this translates to: data that are to be used together are to be stored together (i.e. in a single shard)....
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51 views

How To Manage Random Data Without Repitition?

We have a database design problem of a Learning System. Please can somebody help us ? These are the requirements : A person can register for a module which has "n" number of questions. The person ...
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3answers
520 views

Include logical key on each table vs. join

I'm designing a database that is used to track an inventory item through its lifecycle. I'm currently relating my tables using the previous lifecycle event's ID (for example, a shipment contains the ...
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1answer
151 views

Is a normalized MYSQL DB faster than one organized with comma strings?

I've always used databases with comma-separated id strings, something like +------+--------------+ | id | users | +------+--------------+ |1 |2,4,5,6,12 | +------+--------------+ |...