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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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 ...
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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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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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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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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
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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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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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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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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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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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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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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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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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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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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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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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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, ...
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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 } → { D } { A,B } → { C } { E,B,D } → { C } { E,A,B } → { D } The candidate key is (E,A,B). I do not understand ...
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169 views

Finding all possible minimal covers

I have a relation schema R = {A, B, C} and the following functional dependencies: A → B A → C B → A B → C C → A C → B How many different minimal covers can I derive from this relation schema? I have ...
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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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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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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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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 ...
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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} → { name, start, program } {course_code}...
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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 ...
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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 ...
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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 ...
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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 ...

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