Tagged Questions

This tag is for general database questions; if you question is specific to SQL use that tag instead.

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3
votes
1answer
62 views

Fixing bad data in a database - redo or incremental

I have pseudo-ownership of a fairly old db (original data from 30 years ago; current design is >15 years old). In my opinion, the schema is pretty broken, and one of the implications of this is that ...
1
vote
1answer
55 views

Normalization 3NF and BCNF

If I have the following relation R = (A, B, C, D) And the functional dependencies: A -> B, B -> A, CDB -> A, CDA -> B The candidate keys are CDA and CDB. The third normal form says that ...
11
votes
3answers
1k views

Database schema for a ToDo list

I am trying to make a very simple todo list application with PHP, MySQL, Jquery templating and JSON... However, my schema seems to complicate things in JSON. What's the best way to do it? A new ...
-5
votes
0answers
33 views

Best Program to Create Web Application to Search a Database [on hold]

Apologies if this is a super-basic question, i'm a programming novice. I'm researching how to create a web application to query a database. Specifically, I'd like to make a tool that allows students ...
2
votes
5answers
76 views

Using DDL commands in programming language [duplicate]

Hello I am a student with no industry experience. My question may sound dumb, but, me and my friends were having discussions on use of DDL directly in programming language (any language may be Java, ...
6
votes
4answers
295 views

Heterogeneous Associations - Data Modeling When an Object that Must Relate to One of Many Classes

Suppose you have 3 classes: ClassA, ClassB and ClassC. Now suppose you have a class Message. You want a one-to-many relationship between each one of those three classes and the Message. The goal is ...
1
vote
3answers
67 views

Database design: 4 types of users but have different functionality , separate or one table?

I have 4 types of users: Admins , normal user , company , service provider admins and normal user share some attributes (id .first name ,last name ,phone ,mail) company and service provider share ...
-3
votes
0answers
37 views

email registration confirmation - php - mysql [on hold]

Why won't it send an email confirmation after registering? // Check if the form has been submitted. if (isset($_POST['email1'])) { $errors = array(); // Initialize error array. if ...
1
vote
1answer
52 views

How to associate both a collection and one item of this collection to an entity

I'm working on a project in which I have an entity, we may call Users and another entity Address. I want to define the entity User in a way that an user would have a collection of addresses ...
-1
votes
1answer
48 views

What are common ways to display data in a table [closed]

I've run into this issue a few times in my programming life and I'm wondering if there is a modern, standard way to do this. Basically the idea is you have a huge DB table and you want to display the ...
1
vote
1answer
83 views

What is the point behind building an abstraction layer PDO Adapter class instead of using native PDO?

I have built a PDO adapter class because I thought, at the time anyway, it would be a good idea. After fighting with it, it makes no sense to me. Isn't the design of PDO the way it is to keep you ...
1
vote
1answer
68 views

Transferring information between a web server and a Python backend?

I have been Googling my problem but haven't been able to come up with anything; here's the situation: I have a PHP / MySQL website hosted with 1and1.com. I also have a Python program that runs on a ...
-1
votes
1answer
43 views

Stored procedure in asp.net webforms [duplicate]

Previously while working on database in asp.net I was using stored procedure with no tier architecture. So I was including connection string, crud query etc in every button click event. Then I was ...
0
votes
1answer
62 views

Three-Phase Commit (3PC) question

I've been reading about 3PC in a text book, but there aren't any diagrams or examples, so I found one on wikipedia that I posted below. My question is, what does it mean by "cohorts?" There is no ...
1
vote
0answers
67 views

Three phase commit protocol

I'm trying to understand the three phase commit protocol by reading the wiki page (http://en.wikipedia.org/wiki/Three-phase_commit_protocol#Motivation). In the description for the diagram I posted ...
-1
votes
1answer
78 views

SQLDatabase: Read a lot of data at once and process in memory or read the data when I need it?

I'm not sure how to approach this problem. I require a big chunk of data records from the SQL server. This chunk is based on variables, so I don't know before what records I need. I need to do a large ...
0
votes
0answers
18 views

searching for a user's friends

I have a rails that uses sunspot/solr for searching a number of models in our app. We are now adding a feature for searching for a user's friends. So if I look for "joe" all of my friends named ...
1
vote
1answer
38 views

What should the payload of a “domain event” generated through “change data capture” include?

Using domain driven design and event sourcing ... Given I have a table of 3 columns: (A, B, C) with an existing row of data: (1, 2, 3), when I update the row to contain values (1000, 2, 3) and I run ...
12
votes
8answers
669 views

When does one hard-code actual data values into the code as opposed to using a DB?

A long-standing question for me has been: when do I store data (actual values) in a database table, and when do I store them right in the code? The untold consensus (*) has typically been as such: ...
0
votes
3answers
90 views

Website testable design [duplicate]

I have developed two web services. The main service is a RESTful service (using DB), and another UI service that uses the RESTful service. Say I want to test the UI for now (integration tests), every ...
1
vote
1answer
82 views

Database choice [closed]

I am working on a system where I am replacing and existing Cobol system with C#. For the database I have hit some requirement which I am having a hard time to find complete support for (tried SQLite ...
1
vote
1answer
86 views

Representing list of polymophic objects in db

Let's suppose I have a list of derived objects from some base: class Circle : public Shape; class Rectangle : public Shape; There is object, which has vector of Shape * as member variable: class ...
3
votes
3answers
195 views

Is there a 'standard' SQL that can replace all the various custom versions?

I have been writing SQL for over 10 years now. I am extremely proficient at it and have experience working in SQL Server, Oracle, MySQL, PostgreSQL, etc. While there are multiple standards out there, ...
0
votes
0answers
27 views

How can I aggregate data from separated databases in more efficient way?

Firstm I'm using PostgreSQL 9.3. I'm solving the problem which is to retrieve a data from a separated databases and to render it into a web page. The web project is on the Java (JSF 1.2). Presently ...
-3
votes
1answer
95 views

How can I test a method which aggregates data from a database? [closed]

I'm developing the web Java application and come across the following issue: I'm using jUnit 4.5. Suppose that I have a method which aggregates data from a database for the rendering their to a ...
1
vote
2answers
103 views

When should I implement authentication in a database?

I'm currently embarking on a MongoDB project (a simple user login system), and I notice that there is an option for authentication. Here is the server string, with the userinfo shown as optional ...
2
votes
1answer
81 views

Combine union with distinct

Situation: I need distinct results from two tables, that both have duplicates. I would like to know if I should combine UNION and DISTINCT. Example 1 - Only use distinct SELECT DistinctValue FROM ...
15
votes
4answers
3k views

Databases: Where should the application logic run? [duplicate]

http://highscalability.com/blog/2010/11/9/facebook-uses-non-stored-procedures-to-update-social-graphs.html talks about how Facebook moved logic out of the database into the application in order to ...
0
votes
2answers
68 views

SaaS model, 1DB per client

The context we're building a web-based system and one of the design decisions (database related) was whether to have 1 main DB manage all client data VS having 1 DB per client. After reading a lot ...
0
votes
2answers
59 views

Are the concept of database driven website and the CMS made website same?

I'm having little difficult time of understanding the few logics of web development. Should I call home page, about page (or any other pages of a website whose contents change very rarely and no ...
0
votes
6answers
115 views

Should I rebuild my read only database every time I launch my server?

I'm getting into web development, and I'm trying to get a grip on databases. In an app I want to make, there is a read only database that will be filled up with a large amount of data, which will be ...
1
vote
2answers
202 views

Organise C++ classes around SQL database

My question is about how best to organize C++ classes around a database model, and I understand this may appear very elementary. The software I propose to create will do the following. It is intended ...
0
votes
0answers
107 views

Evaluating local storage for data persistence for small, stand-alone applications

TL;DR - I have a standalone application that will remain relatively small. I'm trying to evaluate between using XML files or a lightweight database for local storage of data that needs to be ...
0
votes
1answer
44 views

How to implement a Daily Recap email of Database records modified the previous day sent to Subscribed Users like Basecamp does?

I am building a Project Management module for SugarCRM. It consists of a "Project" which has information on the project like Name, description, start and completion dates, creator name, status ...
4
votes
3answers
319 views

database design, how to handle freelancers

The context i'm modeling a database for a small ERP system. However I've recently hit a difficult spot that I'm having a hard time wrapping my head around. The logic of it involves a few special ...
1
vote
1answer
123 views

Are CRUD operations intended to be used with collections?

CRUD operations, by definition are... interfaces that permit users to create, remove, modify or retrieve data Implementations of CRUD interfaces can come in various shapes and sometimes they are ...
0
votes
1answer
63 views

Real time middleware system: Direct DB access vs REST API access

I'm developing a complex environment which involves a web application, a mobile app and a real time middleware system which accesses the DB for on-site tag readings. Currently, the web application ...
0
votes
2answers
92 views

Is a mocking framework useful if I'm unit testing a repository/database? [duplicate]

I'm trying to improve my testing skills. I frequently hear about mocking framework to build fake objects (as far as I understand). Right now I need to test my repository (the usual add, remove, update ...
3
votes
2answers
134 views

Is a bad practice create database structure on the runtime?

Im creating a crawler app that will always in the beggining, when the Class constructor, ensure that the basic database structure exists. Is this a bad practice? What is the advantage os creating the ...
2
votes
2answers
79 views

Unit test database insert/remove and atomicity

I create my compact test database. This is a SDF file, embedded as a visual studio resource. When test suite starts this database is copied in %LOCALAPPDATA% so my test can use it. The first method ...
0
votes
1answer
106 views

Properly design program database to reflect organization structure

I'm having trouble setting up my program's database the 'right' way. I was hoping you guys could give me suggestions on doing it properly. I am creating a database+client for a non-profit organization ...
0
votes
0answers
28 views

Storing last polled database timestamp unix

I have a Unix script which is called by a scheduler (CTRL M) every 3 seconds. The script queries an external database(not belonging to my application and therefore I can only query it) to check for ...
0
votes
1answer
111 views

Are there two type of associations between objects or are there just different representations?

I've been spending some time on 're-tuning' some of my OOP understanding, and I've come up against a concept that is confusing me. Lets say I have two objects. A user object and an account object. ...
1
vote
1answer
99 views

Automatic denormalization for a NoSQL database application

We have a use case where we store table-like data, but we know about the schema of the data only at runtime. In our application, a power user defines a schema and normal user can create records and ...
6
votes
3answers
280 views

Proper Response to HTTP Request When Too Much Data is Requested

I'm building an API for an ad serving platform that will allow you to request tracker data for ad campaigns. Campaigns often exceed hundreds of millions of requests, which means there will be many ...
3
votes
7answers
229 views

Are mutliple database calls really significant with a network call for a web API?

At one of my employers, we worked on a REST (but it also applies to SOAP) API. The client, which is the application UI, would make calls over the web (LAN in typical production deployments) to the ...
2
votes
2answers
77 views

Communication/Updates between units of works/entity framework contexts, colliding with user changes

I'm developing a WPF application using Entity Framework for my database communication. The application has a hierarchy of tabs where each tab has a db context. Each tab allows the user to view some ...
1
vote
5answers
135 views

Database design with performance issue and use of views

I am designing database for a school system. I am having to create a lot of tables and a lot of link tables to maintain a structure in the system. I am trying to maintain foreign integrity and trying ...
1
vote
1answer
86 views

How to save appointments in database?

There are 2 entities. One is admin. The task of admin is to define slots for appointments which will be taken by applicants. The admin will choose a default time for the appointments like 10am to ...
3
votes
2answers
130 views

Whether to store all numbers or just their ranges in database for this application

I'm developing a (PHP MySQL) Web App which will sell dynamically generated real time cell phone numbers for cellular companies. A company will ask for, say, a thousand numbers and this app will check ...