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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70 views

ER diagram to tables

Consider the following exam question: Translation: The INCORRECT transformation from the diagram at the right to tables is... This is what I think: a) is incorrect (the column es_C (is_C) does ...
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16 views

Modeling attributes relations in RDBMS/NOSQL?

I have a table to hold the relationship between attributes and documents: I need to support the following queries : give all documents where attrib X='value' give me all documents where attib ...
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21 views

How to have a relation applied only to all entities related to another given entity?

Let's say I'm trying to design an online server for judging a bunch of submissions to several problems. Firstly, each problem has many subtasks (which must go to one problem alone). For each ...
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41 views

Design a database with test table with different answer format

I am designing a database with tables: For each test,there should be a template and one test has many product code and each product code has or has no attribute. tb_template(id,name) ...
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22 views

Data modeling question on Cassandra DB

I'm trying to save events of a month for a user to my Cassandra DB instance. Each month the data will expire and will be removed. The data I try to model will contain user id, date of event and event ...
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16 views

Should I install hadoop on a single node

I just bought a desktop computer with 16GB RAM and 1TB drive, i7-quad core. I will be partitioning off 800GB for Ubuntu so I can do some data science type tasks. Is there any advantage to installing ...
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27 views

Advice on MYSQL DELETE on CASCADE, UPDATE on CASCADE features

I have 2 tables called copyrigihtinfo and sourceinfo and many to many to relationship table cp_src_junction with following data. copyrightinfo table cp_pk cp_info 1 copyright (c) 1991-2000, ...
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33 views

Building an economic time series database with aggregation/dis-aggregation capabilities

I am trying to build a database in MySQL and MS Access that contains economic indicators and financial time series. Initially, I wanted to solve the problem by setting up a table for each major ...
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65 views

Database design for price comparison site - too complex?

I'm working on a regular price comparison site with two exceptions. I want to show price history and also allow users to subscribe to a product with a specific size and color. As a result, I've ended ...
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22 views

Accounting - Dimention table in mysql

I am designing a accounting and mini erp system. I use a date dimension table to track all date related data. In oracle we can have many schema for a database. so we could create each schema for ...
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50 views

draw an ER model using Chen’s notation

hey Guys I need your help with these equations 1- In a faculty office of a department, each faculty has separate printer assigned to her which is connected to her computer. A printer cannot be ...
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37 views

Best practices for storing a small list of booleans

For a new application, I am designing a schema in MySQL to hold the data. It manages document information, with many optional attributes. Among them are lists of 3 to 5 boolean values (checkbox lists ...
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13 views

testing an extraneous attribute in a relation using functional dependency

I am studying the book "Database System Concepts" by sudarshan . In chapter 8.4.3 in a dependency alpha->beta , If A ∈ aplha to check if A is extraneous, let (gamma = alpha − { A}), and check if ...
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12 views

Manager a multivalued attribute?

In the traditional example of a COMPANY database in database design textbooks, we are told that a DEPARTMENT can have only one manager hence Manager should be a single-valued attribute. However, ...
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18 views

What pivot tables to use for User Event Registration with Events and Sub Events

I need to design a database for an application to register and review attendees for events. But There is a complication I don't know how to deal with The event they can register for is for a month, ...
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22 views

How to design a demographics database?

I have a bunch of stores. Each store has the same properties (ethnicity, marital status, income, and so on). Each of those properties has subproperties like (white, black, asian for ethnicity and ...
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36 views

identifying the functional dependencies

I have been reading up on database design and I am having some difficulty constructing functional dependency diagrams from tables. I have the following table. Each salesperson is identified by a ...
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26 views

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 ...
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48 views

Table design for optimum performance

For example let's say I have to create a table called Employee with columns EmployeeID, Name, DOB, Address, DepartmentID[FK]. So I create the table as follows with a primary key and a nonclustered ...
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29 views

Advice on table structure change

I am in the process of converting an Access application that stores and reports evaluations to being web-based using php and mysql. I have converted the structure and data over from Access and I have ...
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34 views

Calculate Quantity On Hand By Location

How can I calculate quantity on hand by location and validate the proposed location quantities against inventory transaction? Currently, I do not track location. I calculate total QoH via the ...
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51 views

Looking for a recipe to merge multiple rows to single row

I have a aggregation table that is written by multiple processors (around 20). Each row has a composite key - location-id, campaign-id,... and aggregate stats about it. I need to merge the ...
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46 views

Should I create a Factless Fact Table or Denormalise my table

I am creating a data warehouse from a store database and I have a question regarding the design of my dimensions and facts. In the store database a table exists for Person, Person_Address and ...
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41 views

Using triggers or php code

I have a table called Salons, which has over 15k Salon names. I have another table which takes count of the pageviews of each salon. My question is that if I want to update reputation of the Salons ...
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29 views

How to apply updates in a “Fan out on write” architecture?

If I copy certain writes to different tables for faster read performance on certain queries(fan out on write), how should I design updates? Since the data is spread over different tables, I'm trying ...
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24 views

calculating Canonical covers

Given F = {AB -> C, A -> BC, B-> A}, compute Fc AB-> C is A extra? {B->C, A-> BC, B->A} 1st possible Fc = {A->BC, B->AC} AB-> C is B extra? {A->C, A->BC, B->A) 2nd possible Fc = {A->BC, ...
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33 views

Tables with same schema in DB for different sources. Bad pattern?

The main purpose of the system being developed is to collect data from different sources, process and standardize it, and then add it to the DB. After information from all sources is collected it ...
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47 views

Billion records mysql performance with large result sets

I'm currently developing an application which will have several mysql tables where 3 of them have very large amounts of records. The thing is that my app will have to sync each account on a hourly ...
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26 views

Is database sharding done on a table level or database level?

I'm new to sharding databases, so I'm trying to wrap my head around it. Let's say we have a database that has 3 tables: Customer, Suppliers and Orders. Each table has 10 million records. I want to ...
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37 views

Last synchronization time between master and slave (replication)

During replication process where a Master is connected with slave. Some times connection between these two goes down. Any options to get the details of the last synchronization time?
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41 views

How to store multiple raster files in postgres / postgis efficiently

This question is partly linked with another question on GIS:stackexchange, but I believe it is has more to do with clever data management. I have a Postgresql server with Postgis extension running ...
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36 views

database design - upvotes for various types

In the early stages of an application I'm developing, I had two relatively simple tables - one for content and one for upvotes. The content table's schema is as roughly: data | text id | integer ...
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36 views

Entity Schema Design

I'm working on an application that has an "entities" system (built before my time) that models users, customers, contractors, vendors, etc. These are all types of people, but have different needs in ...
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23 views

Database & Structure for SaaS reporting software

I'm building a SaaS application to allow users to upload data and perform reporting and analytics on it. The reporting and analytics would be quite simple like grouping and aggregating. This has ...
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206 views

How to select column names that contains specific value from other table's column

Suppose I have table items and logs. Both tables have col1, col2, col3, col4... col(n). col1.. col(n) in table items simply specifies key name (col1 = "beef", col2 = "chicken", col3 = "bacon") ...
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24 views

Two types of rows with mutual fields and unique fields

I have a question about DB design. (MySQL) In my website, users can leave reviews for Stores and Products. Right now, there's a table for stores and a table for products. Each item ('item' = either ...
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21 views

Merge colums from two different databases using phpMyAdmin

Is there a way to: Replace all the data from database1 > table1 > column2 With Data from Database2 > table1 > column2 ONLY under the condition that the ID value in database1 > table1 > column1 ...
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16 views

Handle a Search on 2 Big Tables

Hello i want to realize a exchange system with 2 tables. 1 Table for "the user is looking for" 1 Table for "the user has to share" the Tables are very simple id bigint user_id bigint object_id ...
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45 views

Multi-Tiered Database Design Issue

I am trying to build the multi-level model as demonstrated. When a user creates a campaign they will select some categories and some metros from tables Category and Metro. Those selections will then ...
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42 views

SQL query to fetch results for multiple many to many relationship tables

We are developing a database for storing licensedetails of source code, archives, shareobjects, binary. We parse a detailed build and extract list of source files that make objects, list of objects ...
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15 views

Design and queries for analysis of event-sequences

I will have to store sequences of events with certain properties in a database (MariaDB preferably) and I have some issues regarding the design and queries. The crucial part is the analysis of the ...
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212 views

Suitable database to store GPS track data

I have a network of vehicles. Each vehicle is equipped with a GPS sensor sending data over 3G to my FTP server. As a first solution to test the sensors, each vehicle sensor sends a .csv file to the ...
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74 views

Architecture for huge catalog of products

I need to upgrade my current system of product catalog. For currently I have a 12 000 items in catalog, it's not a lot, but I need to improve them for feature. I have a task to reorganize my database ...
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30 views

many to many relationship tables for four or more master tables

We are developing a database for storing licensedetails of source code, archives, shareobjects, binary. We parse a detailed build and extract list of source files that make objects, list of objects ...
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615 views

Need Help in DFD Diagram for online hotel booking system

Hi friends, I am creating a data flow diagram for online hostel booking system. not sure if i created a correct diagram or not any help would be appreciated. thanks in advance
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59 views

Oracle 11 table design for better performance for reports?

We have a requirement to design a report page. A few factors we have are: number of fields in report is 70 computed fields is going to around 14*8 (based on toggles) a filter is going to have ...
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16 views

How to model mappings at various levels

I'm trying to design the database model for my application and I'm finding it difficult to design the mappings for user access to various entities stored in the database. If access was only ...
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88 views

Storing DB credentials in an application source code?

I am making an app which connects to a DB, and the app will have plenty different userslogins. Is it a good design choice to have a specific DB login/password for the application, using which the ...
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44 views

DB design, when to split out into schemas

I am building a storage solution to store important themes/concepts referenced in books. At a high level the system will contain one or more catalogs and each catalog will contain one or more books. ...
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16 views

How to test if a model is erroneous?

i am trying to realize why the following model is erroneous(or not). i am taking a database course and while i was studying I've found that model.