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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How can I improve my table design for different types of an entity?

Consider an accounting system as an example. I have an Entity called Client. Client can be of different types, with different fields applicable to different types. I consider creating separate tables ...
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1answer
44 views

Personal and Global messaging database design

I am trying to implement a database design system that will be sending messages to a person(thus 1 to 1) or many persons (1 to many). table --users |u_id | Name | | ...
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2answers
24 views

query multiple unrelated tables

Just learning mysql and db so guess this is a general schema design question. Say i have 10 different types of widgets and each widget transaction has a date, amount and 8 other unique columns to that ...
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2answers
50 views

One table with a flag or two tables

I have a problem with the design of a database: In my Android application i need to store the upload (the status, so if the file is in upload it will report the % of the upload) of a file and a list ...
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1answer
27 views

Understanding how relationship sides works

So, I have this relations on my tables (see image) and I need to understand some things. I'll enumerate what I understand and what I need from yours is to say if I'm right or not and in case I'm not ...
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1answer
570 views

How do you query supertypes to get subtype data?

I'm a bit of a DBA newbie here (coming from a programming background having to fill the role of a DBA), so please excuse by blantant and somewhat basic ignorance. Using a simple relationship between ...
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0answers
90 views

eCommerce product table design - MySQL

I am designing database for an web application, I have designed the product and specification details database as follows, create table pr_size ( size_id int not null auto_increment, ...
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2answers
791 views

Choosing MyISAM over InnoDB for these project requirements; and long term options

Sorry for the long post, but I had to give as much info as possible to make this very vague question more specific. My project's aim is to let users search a (huge) database of variety of products. ...
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1answer
18 views

compare file-based systems and a relational database

I don't know the exact difference of both can you please compare file-based systems and a relational database?
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1answer
60 views

Get data from Berkeley DB with Java [closed]

I have a basic Java program which can list data from Berkeley DB database. The question is how I can list the database scheme to see what object are available? Unfortunately I don't have information ...
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0answers
17 views

Redesign tables, multiple foreign key and related table to same table

Hello I have this database: Table Teams is used in each one table. Match table contains teamA and teamB and round contains team that win the SET and team that start the set. But I dont know how I ...
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1answer
51 views

How to model ski rental equipment

I've spent a good amount at time at looking at related posts regarding products for rent but still have a few unanswered questions. If we consider the just the requirements at hand which is how to ...
2
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1answer
34 views

Table income and expense is better to have it together or apart

I am developing a small system where I have to record incomes and expenses of the company, and even I can not determine if the income and expense table should be in one table or in separate tables. ...
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1answer
28 views

How to create trigger with NOT FOR REPLICATION

I tried adding "NOT FOR REPLICATION " in many parts in the below code but ended up in the below code. I searched a lot for an example where I can see how its done with a trigger. Can any one show me ...
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1answer
29 views

Need DDL for an Oracle Table that would be 1 row = 1 8K Block

For performance testing in our performance environment we want a means to turn over SGA the way production does. Our performance environment is a fraction of production and production's very nature ...
0
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1answer
62 views

Different type of column

Maybe the title is misleading but I'll try to explain what I'm trying to do. I'm building an e-commerce site. I have my products and my order. I want add constrains on how the order will be deliver ...
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1answer
68 views

Best relationship database design to manage types for different entities

Suppose we have to manage phone types for: Clients, Employees and Suppliers. Each of these can have multiple phone numbers, so for better management I would like to add phone type. Each entity can ...
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0answers
109 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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1answer
135 views

Horizontal schema vs Vertical schema

I am but a modest SQL DBA. I would like to request your advice on the design of the central part of our new proposed database. Brent Ozar had something to say about this: Building A SQL table ...
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0answers
411 views

Need help to create chat application database schema?

I am developing a chat application in asp.net using SignalR. Client requirements are: Admin can create different chat rooms e.g. (News Room, Sports Room, Android Room etc) Registered users can ...
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2answers
33 views

Do I need foreign keys in ORMs?

Object Relational Mapping (take ActiveRecord and Rails, for example) allows a programmer to define relations between models, and callbacks on delete. So my question is: do I still need to define ...
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5answers
7k views

In SQL, is it composite or compound keys?

About SQL (Computing/Databases): When we have two or more fields in a table that, together, identify its records uniquely, what's the proper way of calling them? Composite or compound keys? I've ...
2
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1answer
46 views

Optimal table design for a medical center rental service and recurrent shifts

I'm trying to figure out the optimal design for the following situation I'm being presented. I'm developing a medical web application with MySQL as db engine. A medical center has 14-16 offices/rooms ...
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0answers
92 views

How do you think in NoSQL? [closed]

I'm from the pre-nosql era and am rather comfortable with SQL. However, I cringe whenever someone suggests using a NoSQL database for the "upcoming" project. There are some major problems that I'm ...
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3answers
116 views

Many one-to-many relationships between two tables

In the process of creating a small database for a therapeutic boarding school with Access 2013, I have a problem when designing the relational database model. Two times at least, I ran into a ...
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1answer
89 views

What is a good/healthy mysql query execution time?

What is a good/healthy mysql query execution time? To my calculations: The site gets 1000 unique visitors per hr 10 page view for each unique visitor 5 minutes for each unique visitor ...
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2answers
54 views

Help required to design a database [closed]

Firstly I would like to apologies if this is not the correct place to ask this question but I know how good community spirit is around here from my time in Stack Overflow. I am very new to the world ...
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2answers
170 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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0answers
42 views

Dealing with Multiple User Roles

I'm working on a project based on a CMS, where there is a built-in roles table. However, the CMS allows a user to have one role only using role_id And these are the requirements that struggling me: ...
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0answers
13 views

Trying to get BCNF out of this relation

The table is: Employee ( EID, Ename, PID, ProjectName, MID, ManagerName ) For the functional dependencies I got: EID==>(Ename) PID==>(ProjectName) ...
3
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1answer
78 views

Row Level security or Multiple Tables

Im looking for documentation on best practices for the following scenario. A hosted application contains some "global" data and some "Per-tenant" data. A "Tenant" should have no access to another ...
2
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1answer
25 views

Save different account types in a database

I have the following issue. In one application (imagine a messaging/e-mail app on your smartphone), the user enters its accounts and gets information from the server displayed. I need to store the ...
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7answers
2k views

Is polling the only way for updating app's data from a database?

An application needs to have data as more freshly updated from a database as possible. In such a case, is there any other way for getting the data, besides of a timer based requesting (polling) the ...
38
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10answers
4k views

What are the arguments against or for putting application logic in the database layer?

NOTE The audience of programmers.se and dba.se is different, and will have different viewpoints, so in this instance I think it's valid to duplicate What are the arguments against or for putting ...
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2answers
127 views

Handling expiration in a course registration or ticketing system

I want to restructure the database for a web application I inherited for handling summer camp registrations, but my question is relevant to any event registration or ticketing system. My question is ...
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2answers
43 views

Designing a Course Equivalency Database

I am trying to create a database to store information regarding equivalent courses transferring from one school to another. I am struggling to conceptualize the relationship in a way that can ...
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6answers
468 views

Database Normalization - Can one field point to another?

This may sound like a dumb question, but I am a software developer new to database design... So the concept makes sense to me, but maybe this doesn't carry-- Is it possible for a field in a record ...
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0answers
17 views

Optimize finding the next batch of data from A to be crunched and inserted into B

I'm using PostgreSQL to store data produced by a large distributed computation. There are several stages to this computation; the idiom we've settled on is that there's a table containing the results ...
0
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1answer
53 views

Problem creating database using default mdf and ldf path

I'm trying to create a database using the default paths on several SQL Servers at once. To achieve this I'm trying to use a script that should create the database on each server, however I've run into ...
0
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1answer
62 views

Creating and designing Air Trafic Control System [closed]

I'm having a class about Database management system, and the prof. gave us a project regarding Air traffic controller system, exact question is "Design and create a system which can manage ...
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1answer
58 views

Can I get some comments on my database design? [closed]

I have designed a database for my institute. Here I have attached my design for better understanding. I am expecting your reviews who are professional for the database design.
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2answers
62 views

Best way to store immutable/read-only copies of data for logging?

I'm storing data about tasks like so TASK (id, name, employee_id, machine_id, ...) For logging purposes I would like to store any information about that TASK once it was made. Since the reference ...
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1answer
57 views

Documenting a collection of databases and their relationships with each other

As part of a project I'm currently involved with we need to identify where various data points are held within existing systems, with a view to integrating them into our central integration engine. ...
2
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2answers
211 views

Design of an application log database

We are generating logs like following example(this is a table no actual pipes): 2014-06-10 09:00:03.457 | Channel1 | Operation3 | Function15 | 15ms 2014-06-10 09:00:08.245 | Channel2 | Operation5 | ...
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1answer
52 views

Should I use a surrogate key in a mapping table?

I am deploying a mapping table which connects Items to ItemGroups Though an Item will only ever be in a single ItemGroup please accept a priori it is not appropriate in my use case to append a column ...
2
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0answers
48 views

“Wide” vs “Long” Database Structure - Is there a logic when to use which? [duplicate]

I'm currently setting up a database to house records for an application I'm writing and am trying to come up with the most efficient DB structure to use... Of course I know that there are as many ...
0
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1answer
32 views

SQL - Query on table creation, referential integrity

Please let us know what does the below definition means on table creation. CREATE TABLE A(w INT PRIMARY KEY); CREATE TABLE B(x INT PRIMARY KEY REFERENCES A(w) ON SET NULL) As per my understanding, ...
2
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1answer
59 views

Review database schema / thought process

Please review my thoughts below. It is written in an authoritative style because it is the most succinct, not because I am competent. Please poke as many holes as possible. I am trying to create a ...
2
votes
1answer
122 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 ...
3
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1answer
356 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 ...