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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Array column vs another table when the relationship is quite small

The Data I am creating a table of cities and their zip codes for the United States. Some zip codes have a list of acceptable cities, as designated by the USPS. For example, the zip code 36613 is ...
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1answer
116 views

Is it ok to create additional column for helping other column to be a PK?

Let's say a Person can have more than one nickname. He(she) must enter his(her) nicknames alongside with other details: Here is the table columns: User_Id, Nickame, Age Of course, for now there ...
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4answers
149 views

Row for each date, or 31 columns?

Currently I have a system whose front-end looks like this: The following query: SELECT `l`.*, `s`.`month`, `s`.`year` FROM `summarylines` `l` JOIN `summaries` `s` ON `l`...
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39 views

Should I create many ID for a same Person/entity in my DB?

In my model, I must store the name of the teacher of some kids and the classroom in which the teachers work, let’s say. All of the hundreds of teachers in the schools have 1 and only 1 classroom, ...
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95 views

Problems in Choosing Foreign Keys :S

I am designing my very first relational database. I am now in the conceptual design, building tables and views, selecting the primary and foreign keys and normalizing everything. But now, I am stock ...
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87 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 | +------+--------------+ ...
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79 views

Single table or multiple table design when records have a clear distinction but are queried together?

Let's say I have the following types of recurring data (all types periodically come in). Post (Title, Summary, Text, Timestamp) Image (URL, Caption, Timestamp) Event (StartDate, EndDate, Title, ...
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1answer
103 views

I created a DB schema for a project relating to collecting comments for web pages, is relational the way to go and how are my relationships?

I'm curious if relational DB is the way to go, if the current relationships in the diagram make sense, and whether it will bode well for coding.
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1answer
185 views

Modeling discounts - Product specific and Customer specific discounts

I have a reasonably simple database but have the following problem: I'm modeling a store + a lot of non-relevant stuff database. I have the following problem. I want to allow for specific products to ...
2
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2answers
931 views

Modeling invoices and orders

I have a problem in modeling a database that contains orders and invoices. Actually it's more of a problem from a business point of view, but it's related to modeling the database nonetheless. Model ...
2
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1answer
54 views

Database Table Design

I would like to ask couple of questions regarding my schema table design. I have the following data coming from an external database where I do not have any control over it. PROD_NO PROD_NAME ...
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44 views

Nullable Fields to Separate Table?

My website has a form page that has radio buttons yes|no corresponding to 7 questions. When the user selects yes, the user needs to specify a value (either a location, name, or medical condition, ...
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4answers
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Is there a tool to check if my database is normalized to the third normal form?

I learned about normalization recently, and understand how important it is when implementing a new schema. How can I check if my database is 2NF or 3NF compliant ? Manual review is a sure option, ...
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1answer
51 views

How to satisfy 1NF with food ingredients?

Take the below table as an example of my situation. How would you organise ingredients so that the values are atomic and satisfy 1NF? Product Code Manufacturer Product Name ...
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1answer
87 views

Duplicate records referenced across different databases

I have a table holding 'People' data (about 70K records) that coexists with an 'Address' table so there's one AddressID per every person in the 'People' table. The idea was to centralize the data in ...
3
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1answer
56 views

Should I create a extra relation-table when I have two columns in one table referencing to one column in another table

My problem is best explained by example: Suppose I have a database about chess games and players. Which one of the following structures should I choose Option 1) player (player_id,name... etc) ...
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1answer
38 views

Big Size Database and increasing number of users [closed]

Me and my colleagues are using quite big size normalized database. Basically it's used for warehouse management and daily minimum 100 of the user perform data manipulation operations. 80% of the ...
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1answer
338 views

Decompose Relation R(ABCDE) in 2nf and 3nf

Given relation R(ABCDE) with functional dependencies A->C B->D AB->E Given: AB is the primary key. I know that this relation is in 1NF because of partial dependencies A->C and B->D Now how I ...
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1answer
56 views

Does schema normalization enhances query efficiency

I understand the importance of normalization in reducing data redundancy and various anomalies but I am wondering if it can also enhance the performance of your query?
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285 views

Is It Needed to Normalize of Date Columns

I am designing a small database with relatively small data. The question is about normalization of Datetime columns. The dates of year occured many times and should I create a Days tables with a ...
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1answer
222 views

Find the functional dependencies that hold in a relation

There is a question in my book that asks the following: Suppose we have relation R ( A ,B ,C ,D ,E ) , with some set of FD’s, and we wish to project those FD’s onto relation S(A, B, C). Give the ...
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92 views

Superkeys of this relation

I am trying to find the superkeys of this relation, but I am having troubles finding out how many superkeys there are and exactly what they are. I figured out that the candidate keys were {A},{B},{C},{...
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0answers
53 views

Method to Obtain LossLess Join BCNF Decomposition

I have been told a way to obtain loss less join BCNF but I don't know how to calculate candidate keys(also called super key in some cases) and trivial Dependency. I have been given a relation R = (...
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1answer
63 views

Normilsation - 2NF and 3NF

I've been through several questions and youtube tutorials, i understand that 2NF is removing the partial dependencies and 3NF is the transitive ones, but i can't get my head around how the following ...
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90 views

Normalization and multivalued attributes

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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0answers
100 views

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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133 views

Multilingual Article/ Category database design

I wasn't getting any answers over at Programmers and was advised to go over here instead... I wanted to make a design for a multilingual database and after having drawn it up have arrived at 5 ...
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1answer
37 views

Seeking help for my ASP Project. (ERD Correction Required)

I am doing this simple ASP project for my uni, just wondering if you can guys direct me or give me some advice. Project Idea is to create a recipe website which will allow users to add recipes and ...
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68 views

Two id columns in one detail table

Let's I have two tables(I have removed some columns for brevity): ADULTS -> ID CHILDS -> ID And I have one table which includes detials about these persons like that: USERS-> ADULT_ID, ...
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1answer
65 views

Normalization for three somehow identical tables

These three tables are nearly identical. But, there are some exceptions. But, I can't find best normalized structure. Could you please help me? Here is the informations must be hold in database: 1)...
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1answer
52 views

Why wouldn't I put the single preferred option into its own table, instead of having a 'Preferred' column?

In similar spirit to How to implement a 'default' flag that can only be set on a single row I would like to specify that, for any given list of possible names for a business, only one of the ...
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1answer
68 views

Create database unique Surrogate Keys without using GUID’s

What is the best way to get database unique surrogate keys in Microsoft SQL Server when using something like “auto increment” as opposed to GUID's. The purpose is to increase performance over using ...
2
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1answer
54 views

On modeling pairs with a possibly empty second element

EDIT: I've made the post significantly shorter. I hope it's more digestible now. Consider the following schema: CREATE TABLE X ( x TEXT PRIMARY KEY ); CREATE TABLE Y ( y TEXT PRIMARY ...
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146 views

Transforming table to third normal form

I have a table like this: L(A, B, C, D, E) and functional dependencies are: AB -> CDE C -> D D -> B D -> E I need to transform this table into 3NF. I think it's not even in 2NF. I ...
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33 views

Trying to get BCNF out of this relation

The table is: Employee ( EID, Ename, PID, ProjectName, MID, ManagerName ) For the functional dependencies I got: EID==>(Ename) PID==>(ProjectName) MID==>(...
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1answer
181 views

Normalization to 2NF and 3NF

I solved this example to determine 2NF and 3NF. I would like to check if my answer is correct. Can somebody check the 2NF and 3NF of this example, please? R( A B C D E F G H I J) with functional ...
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2answers
54 views

How to normalize a table that contains a CK not included in the PK?

I have the following table. The PK is model_ID. Assuming that the modelName field is unique(that is, no two brands can have an identical modelName), there is a transitive dependency between modelName ...
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1answer
171 views

Normalizing: when to apply 2NF and 3NF [closed]

I am taking college classes in relational databases for half a year now. As an assignment get to normalize data with 1NF, 2NF and 3NF. I do not find any difficulties making my schema compatible with ...
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1answer
33 views

Using part of a compound key as foreign key

We have the following situation, in which we have three tables: Article ------- - Id (PK) - Supplier_Id - Supplier_Contactperson_Id - Name Supplier --------- - Id (PK) - Name SupplierContactperson -...
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3answers
2k views

how to convert a table into second normal form

I am really struggling to convert the table into second normal form ive tryed examples which are much easier however i can't seem to be able to identify the keys for this one and work my way forward. ...
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1answer
707 views

Dependency preserving and lossless join decompositions

I have a relation: R = {A, B, C, D, E, F, G, H, I, J} And a set of functional dependencies: G = {AB -> C, A -> DE, B -> F, F -> GH, and D -> IJ} I ended up decomposing into two ...
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1answer
132 views

Clarification for database creation and relations

I've trying to make database with few tables and relations between them. As I'm not very good in databases at all I need some clarifications. The idea is to connect table with table_1, table_2 and ...
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1answer
452 views

normalization NF1, NF2, NF3 [closed]

Pls I need an urgent help ,Can you create a Student school Transcript normalization NF1, NF2, NF3 in excel..... I actually need for someone to help me create a database of " Student School ...
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2answers
227 views

Train Fare Database Normalisation

I have a database to normalize. The database has details of train ticket fares. The trains have different fares depending on the distance and I have to store these fares in the database It is not an ...
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1answer
113 views

what should be the good normalization for the following scenario?

ITS JUST FAKE TABLE DATA TO SIMPLIFY MY PROBLEM I have tables ,, Users , shirts, pants, belts .... each will have some data... so by some research i have made some scenarios of links between the ...
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1answer
109 views

Index optimization on a view using a full outer join

Table structure: Foo FooChild Bar --- -------- --- ID ID ID Date FooID Date ...
2
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1answer
335 views

How to model schedule and keep good constraints?

I have some data that I am having a hard time modeling. Particularly, I am unsure of how I can ensure that I have unique data. This is for a schedule where I am assigning teams to stores. A team will ...
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1answer
286 views

Database Normal Form (financial statement)

I would like some advice on how to design the database for financial statement data which objectively addresses the tradeoffs between usability, performance, maintenance and adherence to normal form. ...
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2k views

What normal form does a surrogate key violate?

I have following question: "What normal form does a surrogate key violate?" My thought was the 3rd normal form, but I'm not quite sure it's just an assumption i am making. Could someone explain that ...
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why this FD make 3NF?

Question like this: Consider the relation scheme ABCDEF satisfying the following functional dependencies: BC --> ADEF CD --> B E --> D BC is a key and designated as primary. Explain why the ...