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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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... (About ...
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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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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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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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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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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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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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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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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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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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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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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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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 |
+------+--------------+
|...
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What should we do when same column fields occurring multiple time in many tables?
I have more than 20 tables in my database. There are some columns which occur in almost all of the tables. In that case what should I do? Do I put all those columns in every table or is there a better ...
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Is the table in 3NF?
I am creating a relational database - a library management system. I want to show an example where I normalize the data from 2NF to 3NF. My example of 2NF looks like
The definition of third normal ...
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Data normalization (from 0NF to 1NF)
I am designing a relational database in mySQL - a library management system. I want to show examples of the data in 1NF, 2NF, 3NF, BCNF, etc. My example of 1NF looks something like this
"A relation ...
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unusual relation, binary aspect
I have question very unusual for databases. I’m not a good English speaker, but good English reader :) so for explanation I’ll give you examples.
Part1
In MySQL, I have two tables with relations ...
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SQL Server vs SOLR (Or any document db)
I have my "customer" data in a normalized sql server database.
Getting out the customer data in my app is taking too long. This is because I have to go to 10+ tables to get all the data I need.
My ...
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Which one is best solution for future database structure?
I'm working on a big web application. so i need to create user_preference_table it has the marks for every users for each attributes. here attributes are games so in the user_preference_table i need ...
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Denormalized tables within OLTP database
My company has a product centered around a fairly normalized mssql server database. At this point we have several reports and a web application that needs the data in a much flatter fashion to ...
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Replace relational database with "poor" design in software product with non-relational DB? [closed]
Edit: This question is about how to deal with many issues that arose from a overall system design, which made parts of the system deviate from common standards. For example, managing everything in the ...
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Best way to create relationship between multiple tables
I have a question about how to best handle a table that would be shared among multiple relationships, but shouldn't really be joined with all these tables. For example, suppose I have a table that has ...
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Best practice database design - user rating tables
I want to create a table to store user ratings of items for collaborative filtering algorithms. So far my table looks like this:
IID | UID | Rating
i.e.
item ID |user id |rating.
From ...
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Denormalization Strategies: When is it appropriate to create redundancy for faster querying?
So I sometimes see databases purposely add redundant information for faster querying. I saw that this was mentioned here but I was wondering when would this be better than indexing, or creating a view?...
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Should I create separate table or have the information as columns in the same table
Sorry for the title but I could not find anything better that could suit my needs. I'm designing the database of a Document Management (Circulation) application. There are two types of documents - A ...
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Should I denormalize lat & lon on area searches?
I run a hobby web site for tabletop gamers. They can search based on postal code in a radius round their location. As I consider adding new countries, my best option seem to be silo'ing the geo ...
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Store millions of rows of denomalized data or some SQL magic?
My DBA experience doesn't go much further than simple storage + retrieval of CMS style data - so this may be a silly question, I don't know!
I have a problem whereby I need to lookup or calculate ...
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Database Normalization
If someone could guide me on helping me understand if my results are correct I would appreciate that. Let's say I have the following table:
BOOK (BookTitle, AuthorName, BookType, ListPrice, ...
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Denormalizing to speed up inserts
I have a MySQL InnoDb table with approximately 40 million rows and the following columns:
param1 (int),
param2 (int),
param3 (int),
geo (char2),
value1 (bigint),
value2 (bigint)
I have an ...
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Decomposing table into BCNF that preserves dependencies
I have a relation like
R(A,B,C)
and dependencies like
A->B , B->C , A->C
I think the relation is in 2NF as candidate key is A. AFAIK when there is only one candidate key then the relation ...
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Database Over Normalized [closed]
How can you tell when a database is over normalized? Example: I have a database for employee. These are the following tables involved:
User - contains email, password, companyId
Profile - profile of ...
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Will a specific denormalization increase performance in a specific scenario?
Suppose I have a table with fields | a | b | c | d | ... | z | which contains millions of records and which will serve millions of queries a day. And the field z holds the id of some parameter which ...
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Denormalize Design Modification
Our DBA is on medical leave, I am just a developer trying to do my part. Initially, the bean counters were going to use quickbooks. However, after seeing how much time they could save with custom ...
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Are de-normalised tables preferred in any aspect of a project? [closed]
While going through interview , My Interviewer asked me a question about Denormalization of tables and its usage in applications.
On guess, I answered, Yes it might be. Being denormalized , you have ...
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Database denormalization: multiple rows into single column. How bad is it? [duplicate]
We have few join-heavy queries to our SQL Server 2008 database and in an attempt to optimize them I thought of having a view that would produce this
OrderID Number Traveller
1 102 ...
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