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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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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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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22 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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2answers
87 views

Daily snapshot fact table

I have a list of products per costumer. Costumers can delete or add products to their list. I want to know in each day what is the list of products (and count) by costumer. My first approach is to ...
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10 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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4 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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21 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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1answer
47 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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49 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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2answers
119 views

Database design for excel-like data

The task I need to store the some values in sequence in the database. The data looks just like a sequence of numbers. Here is an example of the data: Val_1 Val_2 Val_3 ... ...
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28 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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102 views

Database scheme for product tracking

I'm in the progress of creating a separate login for users who want to track specific product shippings. So I got the tables: Products (Id, Name, Color, Description, ...) Used for storing the ...
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using the wordpress approach for storing taxonomies

multiple tables vs single table a user table will not need every social link in the database column, since every one will not enter all their social links and are used only on user profile ...
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1answer
47 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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1answer
147 views

User Table Design

I am designing for an ecommerce application, I need to know how to implement the following task. There are 2 options, Unregistered Users (Free Listing). Registered Users. In this the unregistered ...
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1answer
31 views

Design for hierarchical embedded database

The goal is to construct a hierarchical database of Objects having the following format: TypeA -> ObjectA [values, contains ObjectB*, ObjectC*, etc.] TypeB -> ObjectB [values, contains ...
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1answer
164 views

SQL table architecture

I'm looking for a SQL architecture solution for the following problem. The idea is that I have a validation form that contains the client's data. Each client can log in to his account and edit his ...
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1answer
62 views

Proper implementation of child (derived) table PK/FK during single and multiple inheritance hard coded generalization physical data model

Below is an image of hard coded generalization UML logical model of entities. I'd like to implement these classes as tables in a physical data model. Two derived classes/entities (Class2 and ...
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3answers
331 views

Rent weekly cost database design

I have a database which contains a table BUILDING with in each row details about some building, another table BUILDING_UNIT contains rows with details about a single building unit which refers with a ...
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2answers
2k views

How can primary keys in a Netezza table be indexed?

What is the best way to index a Netezza fact table with lots of primary keys. For now, let's suppose we have 10 primary keys. This table is mainly used to store meta data about our database. ...
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29 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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2answers
144 views

Usage of foreign key when the referenced table data will not change

I have to design a table where user has 10 fields and 6 are dropdown. Some are single selections and some multiple. Dropdown data is supposed to change very rarely. For e.g., the user is presented ...
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1answer
684 views

Designing a database for a site that stores content from multiple services?

I'm building a site that implements David Allen's Getting Things Done that pulls in your email, Facebook newsfeed, tweets from those you follow on Twitter, and more services are planned. The problem ...
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4answers
77 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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1answer
36 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
58 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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2answers
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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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2answers
303 views

multivalued weak key in ER database modeling

I was wondering since i didnt find out any clarification for this. I want to store movies that exist in different formats (dvd, bluray etc) and the price for each format differs from each other as ...
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61 views

Does this medical database look correct?

I'm pretty new to databases and I'm trying to create some schemas. I've been working away at this one for a while, but I can't help feeling that it doesn't look right. Essentially I have the ...
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1answer
55 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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1answer
59 views

Which database (Graph, Riak, etc.) would most aptly solve the following problem?

I am working on a project and was wondering if a Graph database would best solve the following problem: (This is a simplified question) Say that you have a list of friends and you want to see when ...
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1answer
108 views

Best Approach to storing chat history?

I'm building a chat application (Yes, another one :P) and am really curious about the best way to store a chat's history(String username, String Message, Time, and possibly string channel depending on ...
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1answer
167 views

What is Transaction Path Analysis?

I came across the term Transaction Path Analysis which I am not familiar with. A Google search resulted in only a few results, most of which seem to assume everyone knows what it means. From these my ...
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1answer
62 views

Help with “Flexible” vs Fixed Tables

We are designing a database in SQL Server to handle sales commissions. A diagram of the current schema looks like this: There are only a couple of us on the project, and our boss dropped this ...
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1answer
77 views

Designing a reservation system schema

I am not sure if this has been asked before, however I am tasked with designing a new reservation system for my organization We have an older system which simply stored the booking in a table, and it ...
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1answer
17 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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1answer
42 views

Is there any way MySQL can list relationship cardinality between two entities?

I am working on the project where I have to analyse the MySQL schema. As a part of schema information, I want to list down relationship cardinality between different relations. Does MySQL stores ...
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1answer
24 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 ...
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1answer
283 views

Learning to draw entity relational diagram

I am trying to learn entity relationship diagram, following question is the objective. Information consulting firm has number of offices with employees. The employees can move offices depend on the ...
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1answer
60 views

representation in ms-access

I have a database in microsoft access. I want to know how to look up a singular datum from a reference table giving a dynamic set of values. Here is a representation of what I mean: I have the ...
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1answer
78 views

What's better here - a single column or multicolumn primary key?

Let's assume you have a table groups and a table item. Each item belongs to exactly one group. It is an inherent part of that group. An item cannot exist outside of a group and it cannot be moved to ...
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20 views

Basic Design Question about one to many in a table

Sorry for the basic question but I am new to all of this! Say I have a table named Runs, and each table has Run: id (primary_key) data (String - path to a data file) status timestamp ... ...
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1answer
205 views

Designing Simple Schema for Disaggregation of Demand Forecast

I am doing a simple database design task as a training exercise where I have to come up with a basic schema design for the following case: I have a parent-child hierarchy of products (example, Raw ...
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1answer
51 views

Modeling a db that has products: What are the good practices/solutions? How to treat grammar variations in the words?

The problem is: A Company belongs to a sector. A Company produces products. A Sector contains products. A Product belongs to sectors. Three entities: Company, Sector and Product. And it's a ...
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6answers
15k views

How to export an ER diagram from an Oracle DB?

I am developing this application with an Oracle database. I haven't been documenting the data model, but now an auditor wants to have an entity relationship diagram of my database. There are many ...
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1answer
27 views

Is it possible (or good practice) to register data upon Deletion of a record? What would be a better solution?

The problem is the following. A company has one or more representatives (a person who speaks on behalf of the company). When a representative is deleted, it's desired to keep it in an list called ...
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1answer
39 views

postgresql bigserial or sequence using jpa

I'm a java developer working with jpa, before to define the indexes in my entities i would like to known which one is faster o better to use?.
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1answer
75 views

Relation between multiple hierarchical taxonomies linked to a single entity

I am working on an online test application which supports multiple choice questions. I have created schema for taxonomy (classification) system to be used with questions. taxonomy(id, name, slug, ...
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3answers
72 views

MySQL vs. Microsoft Access [closed]

I'm trying to aggregate about 500-1000 MS Excel files that deal with various small business issues (inventory, purchase orders, etc) and I'm currently trying to decide what kind of RDMS I should use. ...
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2answers
26 views

MYSQL Indexes when looking up on alternating sets of columns

I have a table that looks like: CREATE TABLE `connections` ( `connection_id` bigint(20) unsigned NOT NULL AUTO_INCREMENT, `service_id` smallint(5) unsigned DEFAULT NULL, `parent_id` bigint(20) ...