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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What is best practice to organize / normalize database tables?

I manage group that uses a database that is about 12 years old. There are more than 200 tables / views that have been created by various people over the years, many of them no longer with us. Most ...
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31 views

Stroring a type of an entry

There is a table estate with numeric fields districtru and districthe (for a name of a district in Russian and Hebrew), which refer to primary keys of the table districts. The districts table has the ...
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265 views

Most efficient way to structure segmented data

I am faced with a set of data which I am currently unsure on how to store efficiently. The data in question relates to a calendar which stores information on two different categories of event which ...
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4answers
336 views

Does my table violate normalization rules?

I am developing an emulator for a game. My item table looks like this: -- ---------------------------- -- Table structure for `items` -- ---------------------------- DROP TABLE IF EXISTS `items`; ...
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2answers
69 views

How to change type from one owner to two different types of owners

I currently have (tables changed): User UserID uniqueidentifier, CompanyID uniqueidentifier, (for future reference) .. more unrelated fields (PK: UserID) UserRating UserID uniqueidentifier, ...
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154 views

Database Design - When to use “attributes” rather than additional columns

I'm wrestling with a schema design issue. I'm attempting to determine when I should add another column instead of making it an "attribute". Rather than adding a numerous columns to a table, I ...
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1k views

Database Design for Questions and Answers

I'm building a website that will host a variety of questionnaires. Each questionnaire has a different number of questions and each question has a different number of answers. I have attempted to ...
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213 views

Mobile Phone & Tariffs

I have designed database tables of Mobile Phones & Tariffs. It should support multiple mobile networks, sale type and the related affiliate. Points (for operators) are vary depending on the ...
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399 views

Normalization: Should common columns of two tables be pulled out into a third table?

Should I further normalize my current design to eliminate redundancies? I have the following tables: empl: standard user table empl_cat: employee "category" empl_admin_cat: administrative ...
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2k views

Why is a Star Schema more normalized than a 3NF Schema?

According to Oracle's documentation, third normal form schemas "may require less data-transformation than more normalized schemas such as star schemas". I'm confused, I thought 3NF is the most ...
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970 views

Database normalization: Describing trait - foreign key to table, or varchar field with value?

My colleagues and I are having a discussion about the normalization of descriptive traits in the database, such as "status" or "type". Let's call the central table of the discussion "Order". In my ...
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376 views

Does this normalized model for artist music records make sense?

I want to make a database about one artist's music records... CD, Vinyl, Cassette, 8 Track, Singles, Ep, Lp, etc... I believe I have a good normalized model that will achieve my needs, however before ...
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145 views

Which tables to create according to relations

We are planning a new system with a new DB (MS SQL Server). We have the following entities and the following relations: Entities: Clubs, Chains, PaymentTypes, etc... Relations: Clubs-Chains (M-M); ...
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Writing to a DKNF database, but reading from a de-normalized table for performance?

Would the following approach be reasonable? The Goal: queries have to be relatively fast, but without the hassles incurred by writing to a de-normalized database. The Context: A database for ...
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2answers
3k views

Is one-to-one relationship normalized?

Consider we have a large set of statistical data for a record; e.g. 20-30 INT columns. Is it better to keep the entire set in one table as they all belong to a record OR creating a another table ...
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1answer
179 views

Reporting Table Design

I'm writing a system that allows users to store values against each week in October and November and each day in December - starting from the first Monday. I'm holding the raw data entered by the ...
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3answers
521 views

shoud we normalize user profile table with fields like interests,musics,videos,sports, etc?

I've read in an article about social networking database schema and saw that they've used varchar for those columns that I mentioned in the question title. It's not normalized! Isn't it better to have ...
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3answers
207 views

is id and phone number enough to uniquely identify a row in phone numbers

Was designing a table a customer_phone_numbers table a while back, which only purpose was to allow us to store as many phone numbers as a user wanted to have on file. I originally came to the ...
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2answers
887 views

Database Schema for an address book with different mailing lists

I'm helping a friend out with taking an old excel, single-page database which contains around 12 different columns that store information about: person first+last name email(s) current address ...
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2answers
290 views

Migrating and normalizing data

We are rewriting a large Django application which uses a MySQL database, and the database schema needs to undergo major modifications. We're also porting the app to use PostgreSQL, for a couple of ...
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583 views

Good reason to denormalize?

I have a database with about 40-50 tables. All but 5 are part of a giant hierarchy of 1:M relationships that all point back to one solitary parent (call it "Project"). Each table is joined to its ...
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1answer
242 views

Normalization and Breaking down tables for InnoDB

I'm designing a web application, something small but deals with lots of read and inserts. Let's say 60% read and 40% writes. My storage engine is InnoDB on MySQL. I have a table called User which has ...
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3answers
136 views

Optimisation Newbie: How much of a 'sin' is redundancy?

I've been developing for a while, but never really had to deal with DB/scaling issues before. That's suddenly changed and I've found myself in the deep end. I have 2 SQL tables, as such: VOTES ...
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How far should you go with normalization?

I have a decent amount of data in a database. I have well formed tables and good relationships between them with some redundancy in my data. But how far should I go with normalization? Are there ...
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2NF decomposition + database normalization

If anyone knows about 2NF I'd greatly appreciate if you could tell me if my understanding of it correct my book does not even mention it (except to say is of "historical significance") and I haven't ...
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2answers
197 views

design of maintenance database

Lets say i am designing a database that tracks maintenance of equipment. Each piece of equipment has various fields that usually don't change eg. ID, model, serial number etc. Some fields change ...
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655 views

Unexpected extremely long query time (~5 minutes using nested WHEN-INs)

For the first time, I am running up against a horrifically long execution time of a MySQL query (~5 minutes). The data in the database is highly (and not arbitrarily) normalized. It very efficient ...
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160 views

Tick boxes and Dropdown

Have a look at the image below: This is "Plain Buger" item - customer can select sauces and extras with it. There are different sizes for Plain Burger. I need to translate this UI into database ...
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3NF Vs 2NF, which is more strict?

Which of these is true: If a table is in 2nd normal-form then it must be in 3rd normal-form. If a table is in 3rd normal-form then it must be in 2nd normal-form. I know only one of them is ...
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Loading multiValued fields into Solr via flat file, and possibly value position preservation in those fields

A hobby web project of mine uses data from many sources, some flat, some highly normalized. My ETL process boils all sources down to one logical table (which is soon to include some multi-valued ...
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634 views

2NF and 3NF How to do it

Given E(ABCDE) ABC are candidate keys Normalize into 2NF and 3NF As far as 2NF is concerned the solution is quite easy: E1(BD), E2(DE), E3(ABC) But with regard to 3NF I think I'm wrong if I say ...
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273 views

Am I violating any NF rule on my database design?

I am a newbie on creating database... I need to create it for my recruitment web application. My application needs to schedule screenings, exams and interviews of applicants and save result in the ...
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1answer
440 views

Boyce Codd Normal Form understanding

I have a knotty (at least for me) problem to solve. Normalize, with respect to Boyce Codd NF, the relational scheme E(A, B, C, D, E, F) by assuming that (A, B, C) is the unique candidate key and ...
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406 views

Multiple values in lookup fields

I know newer versions of MS Access allow multiple selections in lookup fields. For example, if I'm collecting information on my students, I can have a field called Race with lookup values that ...
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95 views

What model design supports both data store backed and free form entries?

I have an application where users are tracking a workflow around producing a derivative work from an existing Book. The derivative work, we'll call "BookDerivative" must have a book that it relates to ...
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3answers
274 views

Does this database table violate normalization rules?

I’m working with Access 2010. I’m developing a database for a public art program – we paint large scale murals on walls. The database tracks blank walls in the city as potential sites for murals. It ...
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3answers
3k views

SQL table design for primary keys (best practice)

I have a User table that contains the following fields ID (Auto-generated GUID) UserName Password FirstName LastName Email AddressID (GUID) This is linked to the table Address (1-1 relation) which ...
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750 views

Confusion in BCNF

I understood all the three normal forms which comes before BCNF but when it comes to the BCNF i am finding it extremely confusing and difficult and over the net also i found no good tutorial on it. ...
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Constraint many to many table between two child tables

New to this exchange site so I hope my question isn't inappropriate. Creating a somewhat normalized database I had one design problem I'm not sure how to handle efficiently. One table has a ...
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272 views

Query regarding normalization of the relations

I am given a case study of Event Management to develop an ER model and based on it its normalization forms and relational schema. Now i have developed my ER Model based on the SRS that i have ...
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654 views

Is DB Normalization done purely based on the primary key or is it done based on all the candidate keys?

I have come across two flavours of the normalization procedure while referring the internet and textbooks. viz. Type 1. Normal forms based only on the primary key. In this type, -> 2NF disallows ...
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404 views

General Question on how to setup db's for a social networking site

I am currently responsible for designing the entire database setup for a start up website. It is quite a responsibility and I want to get it right, not only for the site, but for my own experience. ...
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Normalization: Is it considered compliant to split static, numeric values like a year into their own table?

I am having an interesting discussion with another database designer about normalization. In this example, we have a GameTitles table and each record must contain the year in which the game was ...
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4answers
4k views

Storing arrays of integers in database (for efficient select)

I am creating a database that will store 100.000 (and probably more in the future) users. While this obviously happens in a table with 1 row per user, every user can (and will) store hundreds of ...
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Normalization Exercise Resources

I want to sharpen my database normalization skills. Where can I find good quality beginner-to-advanced level exercises (with solutions) on the web ?
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371 views

Database Design Issues

My question consists of three parts: When can I be sure that my database design is perfect? Is returning to the database design to change some issues (i.e, adding new column, deleting a column, ...
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2answers
930 views

Using IDs from multiple tables in a single column

One of my co-workers created a schema similar to the following. This is a simplified schema including only the parts necessary to address this question. The system rules are as follows: ...
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3answers
3k views

Query to normalize table/combine row text

I have a table (call it oldTable) with columns like so: ID (int),Rank (int),TextLineNumber (int),SomeText (varchar) The primarykey is multi-part: ID+Rank+TextLineNumber. I'm trying to ...
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When to apply normalization in database design

Hello database administrators. Recently, I have been reading about normalization in order to improve my database design skills. However, I am a bit confused about when to apply this technique. Prior ...
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IIS access log to SQL normalization

I am looking for insert IIS 6.0 access log ( 5 servers, and over 400MB daily ) to SQL database. What scares me is the size. There is a lot of information you are duplicating (i.e. site name, url, ...