Database design is the process of specifying the logical and/or physical parts of a database. The goal of database design is to make a representation of some "universe of discourse" - the types of facts, business rules and other requirements that the database is intended to model.

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Rules for Decomposition to 2 NF

I am struggling with the concept of 2NF form. Lets say I have a set of functional dependencies for R1(A,B,C,D,E,H,M,K) Where : B -> M,C AB -> D DH -> E H -> K A -> H Whenever I ...
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71 views

How to generate data for News Feed efficiently like facebook , googleplus , twitter e.t.c?

I have created table as post ( post_id int(15) auto_increment primary key , user_id int(11) , post_text varchar(2000) , post_type int(1), ...
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63 views

What is the advantages of using auto_increment in database as primary key over set of attributes?

I have table as CREATE TABLE circle ( circle_id int(11) auto_increment primary key not null, user_id int (11) not null, title varchar(255) collate utf8_general_ci not null ); CREATE ...
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63 views

What is the strategy of query evaluation in DBMS when Limit is used in query?

I have following tables in database post(post_id , user_id , post_text , parsed_text) ; Comment(comment_id , post_id , user_id , comment_text) ; friend(id , user_id , friend_id ) ; group (id , ...
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25 views

Relationship cardinality different in subclasses

I need to design a concert management database for as a class project. So far I defined an "Event" entity, subclassed in "Festival" and "Concert". Festival is intended to last one night or more and ...
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117 views

Airline reservation system [closed]

I'm making a simple airline reservation system. But I'm not sure about the design decisions I made. Concretely, I'm trying to implement following constraints: each Aircraft can have one or more ...
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77 views

What is the correct way to ensure unique entries in a temporal database design?

I'm having trouble with the design of a temporal database. I need to know how to make sure I have only one active record for any given timeframe for a store. I have read this answer, but I'm afraid I ...
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2answers
56 views

Is my ERD valid for airports,cities and airlines database?

My objective is to make a database of airports, cities and the airlines which provide coverage to them. I asked the question before on stackoverflow and the person told me to break up the ...
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68 views

database design for dynamic menu bar [closed]

I am trying to create a menu bar which will load dynamically on user log in, based on the user roles. Say if the user is an admin he can see all the items listed under the header and if a user is a ...
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40 views

Book about database design patterns [closed]

This question was asked before, but I have different needs. I know how to: query the database with SQL create triggers and stored procedures create databases (with 1:N, N:M and 1:1 relations) ...
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3answers
93 views

Mass data upload from Excel - technology

I am a Developer seeking help in terms of DB technology for a specific requirement. I have done some research but can not conclude with list. Requirement: There will be a web application which will ...
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2answers
241 views

Alternative to EAV for dynamic fields in a star schema data warehouse

I need to support dynamic fields and values in a big datawarehouse for storing API requests log, my user case is that I need to store all API requests query string and able to perform query against ...
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27 views

Enterprise system database strategy [duplicate]

Here is my current database design: Separated databases based on area of domain (Sales, HR, Accounting, Core such as login and menus, etc). Each database has a single service login, each with ...
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71 views

How to design Saas application's database architecture in mysql

I have to develop a Saas application using Yii php framework and mysql. For developing this we have decided to make separate database for each customer. For this I need a effective basic database ...
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25 views

Normalization to BCNF help needed

I have a table with 5 columns as A, B, C, D, and E. The functional dependencies are: AB -> C,D,E BCD -> A BCE -> A,D BD -> E I think AB is the candidate key. I can't find any other candidates. ...
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34 views

Is it OK to duplicate parent field in child table for performance?

I have a very complicated query which involve more than 10 tables. Some parent tables are loaded only to search on one field. I wonder if I can copy this field in the child table (this data is never ...
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38 views

Shared emails in a database [closed]

We lost our database administrator over a year ago - and even then she was promoted into the job internally and sort of learned on the job. Basically I say this to establish that strong data standards ...
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76 views

Database normalization tables

I am creating a database for a very basic website. I have created the tables and put what I thought might be the correct schema, however I am having doubts about it as well as a couple problems. All ...
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332 views

Database design for handling 1 billion rows and counting

We receive real-time GPS data at a rate of around 5000 pr. minute (from 4 TCP servers). Each server uses a single connection to insert the data, and buffers data in between inserts. Every 15 minutes ...
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Difference in the workload related to data-amount and search option

A couple of days ago I was asked why it is necessary to use the first normal form also for separation of names. We have a table which stores private customers (Name+Surname;Information) and business ...
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2answers
83 views

General structure advice for beginner

I am starting my first DB-Driven website project for a mock real estate agency and would like a bit of feedback on my general approach to how I will drive the site with the DB. Specifically I'm ...
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1answer
106 views

How to normalize my db schema for a quiz application?

I am putting together a quiz application. (I'm calling each quiz a "challenge") I have a "challenge" table and a "challenge_question" table which is pretty straightforward. challenge table: id ...
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33 views

more queries vs storing results in database

Environment: Embedded (smartphones) Data Structures: Object Table A: id, field1, field2... Object Table B: id, field1, field2... Object Table C: id, field1, ... , Object A, Object B ... many ...
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66 views

How to design to avoid two-way reference between two tables [duplicate]

I am having a problem with foreign keys between two tables. I am trying to model a relationship between members of a club and their relatives. This is a straightforward many-to-one relationship, with ...
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34 views

How can I handle conditional fields?

I am in the process of designing a database for my company to assist in asset management. I'm not a database administrator, but I had some previous course experience with databases. Our assets are ...
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2answers
68 views

How to deal with circular foreign key

I have two tables: Games( name, current_step, #foreign key to Steps table #other fields... ) Steps( name, game_id, #foreign key to Games table #other fields... ) In other ...
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62 views

Which one is correct and optimized in sql?

Imagine that I have three entities (EntityA, EntityB, EntityC) that can have some images. So there are two ways: Make an image table for each entity. It means that EntityA has a image table named ...
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38 views

database design for storing mobile & tablet attributes

I am developing a site like gsmarena but i am not expert in database design , can any one help me with database design to store mobile attributes like here ...
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Designing a multi-language searchable translation database

Good morning, I am currently building an application where I have different sets of terms(yes could be sentences) or words represented in different languages. Example: english | french | german | ...
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44 views

Decomposing into 2NF

I'm currently studying normalization. I know how to normalize the data for given unnormalized list. But I found this question in our past papers. I don't know how to answer to it. Q. Decompose ...
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1answer
37 views

UK Addresses in 3NF

I am in the process of creating a UK only database which holds information for various sets of people i.e. Staff, Clients etc. The tables for each of these sets of people have an Address, City and ...
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89 views

How much the decision to use ternary or binary relationship influences the accuracy of the model with regards to a given business model?

The question title is very long, so here's a little bit of context to (try to) make it clear. I asked a question regarding ternary relationship. The question was Ternary relationship: what's the ...
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1answer
133 views

Ternary relationship: what's the difference between having single table and having multiple tables?

Consider the following ternary relationship: Suppose that all entities have only two attributes (PK and Name). Here are the tables I derived (5 tables): Sector ------------------------- ...
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105 views

Conversion of simple ERD to Table: is the solution below any good?

Consider the following ERD: Suppose that all entities only have two attributes: a PK plus a name/number. I want to convert that ERD to tables. Is it needed 4 tables (1 for each relationship ...
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56 views

Database analysis

I have database which that store the sold products in Orders Table and another table called Transaction to set the time and the total price for the individual order ,my question is: How to combined ...
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56 views

Should I use SQL Azure to store product descriptions and links to images in Azure Blob

For an html/Css/JQuery public Azure website to be coded using Zurb Foundation html5 responsive framework, I'd like to use SQL Azure (web edition) to store product descriptions and links to images that ...
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1answer
197 views

MySQL Workbench EER Diagram and ENUM data type

I am creating EER model diagram using MySQL Workbench (version : 5.2.47) The version for MySQL, I am using is 5.5.35-0ubuntu0.13.10.2. I have created a schema with 'Default Collation' set to 'utf8 - ...
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34 views

Database structure for maintenance planning

I'm currently working on a solid way of creating a sort of planning system. In this system, I need an productgroup to be made (= category name for a list of items, like cars) with producttype as ...
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80 views

Is this design in 3NF? Why to choose another design not in 3NF

Having the following entities: Objects, Parts, Subparts and Items, and given the following design restrictions: A Part belongs to one and only one Object. A Subpart belongs to one and only one Part. ...
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39 views

ORM for Image model

I'm uncertain as to how a certain table should establish relationships, and I feel as if the solution I came up with is incorrect. The images table is used to store an absolute path on a server ...
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44 views

How to convert this relation to 2NF?

In my Entity Relationship Diagram, an entity type TEACHER had a relationship of TEACH with another entity type called CLASS. CLASS was a week entity type of TEACHER,so when mapping to a Relational ...
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4answers
98 views

Advanced design question related to compound primary keys

As a database design expert, I had a discussion with an academic person about database design and I need some arguments on why some design is bad or not normalized or bad practice. As we cannot ...
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97 views

How to design a database structure for different groups of contacts?

I've been looking around for a while how systems manage their contacts. Most I encounter is creating a people or party table including a type to define the type of people/party. These types are either ...
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1answer
53 views

Create one-to-many to two fields in different table

I have a database where I am trying to figure out how to join a table that contains an object called ModelType. The calibration table contains two fields (EffModel and BkgModel) that are based on a ...
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1answer
88 views

Clustered composite key high fragmentation and fill factor

I've recently made a table to hold the language preferences of my users as follow: CREATE TABLE [dbo].[systemUserLangPreference]( [systemUserID] [int] NOT NULL, [langID] [int] NOT NULL, ...
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100 views

data warehouse design help

I'm struggling with the design phase for a data warehouse. It's not the traditional sales example you find on MSDN or all books etc. I've been tasked with creating an education data warehouse, that ...
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1answer
51 views

Is it Ok to have one table with two relations?

I have an event table that has two kinds of participants. Each event will have many participants of each type. Is it good form to have a separate table for each participant type, each related to the ...
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2answers
49 views

Relations between a imeid, sim chip, and account from a cellphone company?

I've never really had a cellphone (that I owned the account to...long story), but at work we have them, and we want to get a series of relations between accounts, devices (mifi's, tablets, ...
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18 views

Duplicate Data from two column

i have a table which has only two column one is pid(Photo ID) and another one is tid(Tag ID) +-------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | ...
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30 views

Table join inheritance

I create db with Person, Client, Employee, Manager, Developer. I'm interested what is the best way to put the data in tables. In which cases should programmer unite Client in table hierarchy with ...