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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26 views

ERD to data structure

I'm new to databases. I converted my ERD to data structure. Althougt I made sure all the 1NF, 2NF and 3NF are handled, I'm skeptic about it. This is the data structure. Port(PortID(pk), Name, ...
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43 views

A transition table, is it a good idea?

I'm writing an application that stores a project's C++ API representation. For example, I have tables like Class, Function, FunctionParameter, DerivedClass, BaseClass, and so on. Every once in a ...
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51 views

What is the name for a table that keeps track of operations that have been performed on the database?

It's name is Trans_Log It has the following fields: TL_User (database user logged in) TL_WinUser (name of windows user logged in) TL_Date (date of operation?) TL_Type (type of operation / function ...
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23 views

How to create and select entities in MongoDB?

I'm a newbie in MongoDB and I'm trying to understand how to create objects there and how to select them in comparison with relational databases. So I need an example how to perform these things. ...
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33 views

How to reference a table mapping that is not initially known in another table

I have four tables: ExternalName, InternalName, ExternalInternalNameMap, and Transaction. ExternalName and InternalName have a many to many relationship. ExternalInternalNameMap is the junction table ...
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20 views

Advice for a friendship table

For my little project I would like to create a very simple friendship system. And I would like someone to give me some advice/criticise the current design I have. Here is an example of my friend ...
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40 views

School fees database design

I am trying to design a database for a school fee management system. The school is charging some Admission fees , Security for one time but development fund, registration fund on annual basis. but ...
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18 views

How to model a type that's related to one of a number of other types

A generic data modeling question: How would one model the database tables in a case in which an entity of Type A is related to one entity of either Type B or of Type C (but not both). For bonus ...
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52 views

Credit Card database schema

I am not very good in database design so please if you can help me with this. I want to know what will be the best way to store it in mysql database Here is the selection I want as final Select ...
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14 views

Assigning items to containers

I have two tables for separate things: One table for containers, one table for items. They both have things like descriptions, title, and of course ID fields: container_ID and item_ID. My containers ...
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14 views

Should I partition table by time or project_id, or both?

I have a table of event data that is getting slightly large. It's ~10 million records. I want to partition the table to help speed things up. I almost always restrict the query by both the time and ...
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12 views

How to add entries to tables in PostgreSQL if the attributes are reliant on other tables?

The problem that I have is something like this: Users ========= UserID Name Surname User Group ========= GroupID LeaderID Group Leaders ============= LeaderID UserID GroupID The problem arises ...
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29 views

How to combine 3 queries into 1 including set?

I have 3 mysql queries and each does specific job, the problem is I can't figure out how to combine 3 queries into 1. I'll write down all 3 queries and explain what each does, thus you can figure out ...
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19 views

what model should i use for store detections time series in mongodb?

i have cloud site with many hosts and virtual machines inside of it. I receive from some software many different metrics values regarding vms usage (cpu load,free ram,energy consumption and so on). ...
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38 views

All in one table or separate tables for each categories for a clasifieds website?

I am developing a classified website by using ASP.net and my DB is MYSQL. In there I am using a header table to store common records of an ad. like ad title, description, published date like wise. And ...
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34 views

What kind of data cannot be stored economically in a database / data-warehouse?

Someone mentioned this in a presentation but didn't provide any examples. This stuck with me and I am trying to figure out what kind of data couldn't be stored economically in datbases ever since. It ...
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17 views

How to model role and different activities

I am new in the database design and I'm facing this problem, I hope somebody can help me. In my domain we have 3 roles, Non-Supervisor, Supervisor, Manager. I created a Person table and a role table ...
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36 views

Manage orders based off product attributes and quantity

I'm developing a database for an online store in which the Products have multiple attributes and attribute types. ATRIBUTES TYPES atrtype_id name (like size, color...) ATRIBUTES atribute_id ...
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41 views

linking a single table (comment) to multiple tables (article,link,attachment)?

the main idea is that i can post an article , link or an attachment and i can receive comments on each of these types of posts (the structure of the comment is the same) , the problem here is that i ...
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82 views

Multiple user roles with different attributes

I need to design a database that has multiple users, with multiple roles. For instance, a user can be an admin, company, employee, or customer. Each user can have any number of these roles. Right now ...
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42 views

How to store likes to posts in Parse.com database?

In my parse database I have a classed called Post and Like. Should I create a field likes in Post class with Relation<Like> type or there is another better option of storing likes in Parse DB?
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34 views

How to cast as type of a table column?

I have multiple views with union like this: select column1, column2 from mytable union select cast(extcol as nvarchar2(15)), cast(extcol2 as nvarchar2(10)) from exttable But later I change the size ...
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43 views

Database design for varying prices from multiple vendors

I am designing a database where the products are sold in bulk with multiple pricing options, from 4 different vendors. What is the best table configuration to store this information? Id like to be ...
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23 views

Trying to Figure out an ER Diagram for a set of instructions

Below is information about a database and I want to come up with the ER Model. (Im not sure if this is the right place to post this. Im new to this page) professors have an SSN, and a name projects ...
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68 views

MySQL Dynamic columns duplicate value workaround

As the title suggests i have the following code which transposes certain row values into field names, however the problem im having is that the values "closed" & "reopened" may appear in several ...
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30 views

Performance/Maintenance Implications of a Write Heavy Table In An Otherwise Normal “CRUD” Database

We have a small-ish (<100,000 rows) MySQL database (on Amazon RDS). Its supporting a fairly simple read heavy CRUD web application. Currently we're building out a web analytics system. It will ...
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23 views

Database systems with users and sub users accessing the data

I am making a database for school student maintenance. Below is the basic description. There are schools. One school has many staff (i.e: Principles,Teachers, Section Head, Office Staff etc) These ...
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35 views

Designing a correct table structure

We are trying to save the Family History of a particular foreign job applicant. Below are the details we have to save. Familiy Member: Father|Mother|1st Brother| 2nd Brother| 1st Sister| etc etc ...
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86 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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19 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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48 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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35 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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19 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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28 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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48 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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142 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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30 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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73 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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48 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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15 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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23 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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32 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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50 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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29 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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50 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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45 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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60 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 ...