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

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6
votes
4answers
412 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
1answer
48 views

Reduce Operations on Distributed Databases

I would like to ask you about optimizing reduce operations (e.g. count) on multiple databases. Let's say there is a user table that is stored in various countries and sharding is made based on the ...
13
votes
3answers
2k 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 ...
3
votes
1answer
107 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 ...
0
votes
2answers
119 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 ...
1
vote
3answers
268 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 ...
2
votes
5answers
92 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, ...
1
vote
1answer
68 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 ...
15
votes
7answers
1k views

Does it make sense to standardize including a created date and last updated date field on all DB tables?

My boss is currently attempting to apply some development standards to our team, so we had a meeting yesterday to discuss the standards which was mostly going well until she brought up: All DB ...
1
vote
1answer
152 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
121 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
155 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
75 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
3answers
231 views

Pattern / methodology for representing large database records as objects

A bit of background information: We have an old database application written in Access that lets users monitor their workload, and the code is... 'procedural' might be too kind. The vast majority of ...
1
vote
0answers
72 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 ...
12
votes
8answers
739 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: ...
-1
votes
1answer
412 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 ...
1
vote
1answer
88 views

How can I share a managed DBConnection across various objects?

I am implementing what I thought was a simple object wrapper around a database where one object "PartRecord" represents one row of a database table. I want a client to be able to request a given ...
0
votes
0answers
21 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 ...
0
votes
1answer
2k views

Why would I use ElasticSearch if I already use a graph database?

I don't find any deep explanation on the web about a comparison between ElasticSearch and the graph databases. Both are optimized to traverse data. ElasticSearch seems to be optimized for analytics. ...
1
vote
1answer
69 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 ...
0
votes
3answers
116 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 ...
45
votes
13answers
4k views

Is it necessary to create a database with as few tables as possible

Should we create a database structure with a minimum number of tables? Should it be designed in a way that everything stays in one place or is it okay to have more tables? Will it in anyway affect ...
1
vote
1answer
96 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
96 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
220 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, ...
6
votes
4answers
5k views

Handling database schema changes when pushing new versions

During times of heavy development, the database schema changes both rapidly and continuously, and by the time our weekly push to the beta build comes around, the schema has changed so much that the ...
15
votes
4answers
4k 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 ...
1
vote
2answers
119 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 ...
0
votes
0answers
35 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
101 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 ...
0
votes
2answers
89 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
126 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 ...
0
votes
0answers
254 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 ...
3
votes
1answer
154 views

End user query syntax?

I'm making a command line tool that allows end users to query a statically-schemed database; however, I want users to be able to specify boolean matchers in their query (effectively things like "get ...
0
votes
1answer
78 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
352 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
142 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
183 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 ...
13
votes
6answers
8k views

Is there any reason to use varchar over text columns in a database?

Is varchar just a remnant from before text came around, or are there use cases where you would want to use a varchar? (Or char for that matter..) (I use Postgres and MySQL (MyISAM) daily, so those ...
7
votes
5answers
5k views

What is needed to deploy an application that uses Microsofts new LocalDB?

I'd like to know what microsoft components need to be installed for this new LocalDB to run on a users machine. Now in CTP3: SQL Server Express LocalDB LocalDB is a new lightweight deployment ...
0
votes
2answers
211 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
182 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 ...
0
votes
2answers
149 views

Is it a bad practice to keep database schema scripts (DDL) and manipulation (DML) scripts in different modules

we have a project structure like the following "module-shared" module depends on "module-database" module and some other modules depend on "module-shared" but no other module depends on ...
2
votes
2answers
107 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 ...
5
votes
4answers
2k views

What's stopping Oracle from supporting identity (auto-numeric) columns? [closed]

EDIT: As gavenkoa's answer points out, Oracle Database 12c (released a couple of years after this question was asked) has support for Identity Columns. As far as I know, Oracle's RDBMS is one of ...
7
votes
6answers
347 views

How best to handle database refactoring within a team?

We are currently usign a roll-forward approach to DB changes, akin to Migrations, where each developer creates and checks in a script that promotes the latest version of the DB to a new state. ...
0
votes
0answers
36 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
140 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. ...
4
votes
7answers
406 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 ...