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16
votes
3answers
10k views

Is there a list of common usernames to reserve in a new system?

I need to reserve usernames in my new website. These generally fall into three categories 1) usernames no-one should have (eg: admin, user, service, help, root, etc) 2) names of super famous people ...
16
votes
3answers
4k views

How to store prices that have effective dates?

I have a list of products. Each of them is offered by N providers. Each providers quotes us a price for a specific date. That price is effective until that provider decides to set a new price. In ...
16
votes
1answer
7k views

Redis vs Zookeeper

It seems silly to compare these two servers considering that they're meant for very different things. But if you think about it, they can do lots of similar things: store configuration data, ...
15
votes
4answers
1k views

Do I need IDs in my database if the records could be identified by the date?

I am writing my first application for Android and will use the SQLite database so will be trying to limit the size as much as possible, but I think the question applies in general to database design. ...
15
votes
6answers
35k views

How to quickly search through a very large list of strings / records on a database

I have the following problem: I have a database containing more than 2 million records. Each record has a string field X and I want to display a list of records for which field X contains a certain ...
15
votes
8answers
2k views

Handling deleted users - separate or same table?

The scenario is that I've got an expanding set of users, and as time goes by, users will cancel their accounts which we currently mark as 'deleted' (with a flag) in the same table. If users with the ...
15
votes
5answers
1k views

Is having functionality in DB a road block to scalability?

I may not be able to give the right title to the question. But here it is, We are developing financial portal for wealth management. We are expecting over 10000 clients to use the application. The ...
15
votes
6answers
771 views

What do DBAs do? [closed]

Yes, I know they administrate databases. I asked this question because I'd like to get a further insight into the kind of day-to-day duties a DBA might perform, and the real-world business problems ...
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 ...
15
votes
2answers
5k views

What is the difference between collation and character set?

I have a general question about databases. We usually use the term collation with databases. I would like to know how its different from character set. I guess collation is a subset of character set. ...
15
votes
2answers
7k views

Conflict resolution for two-way sync

How do you manage two-way synchronization between a 'main' database server and many 'secondary' servers, in particular conflict resolution, assuming a connection is not always available? For example, ...
13
votes
6answers
2k views

Do You Still Need Indexing After Database Normalization

After you have done a good normalization, do you still need to index the table? How is this going to affect the performance? Will it even affect the performance in some way after a good normalization? ...
13
votes
3answers
3k 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 ...
13
votes
5answers
1k views

Is it the job of programmers to design the database?

I've been a programmer for the past six years. Throughout my career, I have worked on many web applications. Most of the time, when a database was needed, it was given to us (the programmers) or we ...
13
votes
7answers
2k views

Why shouldn't you develop on production database? [duplicate]

I need help with organizing my arguments for why it's MADNESS to develop against production data. Backstory: I started working here six months ago and I noticed we're developing directly against ...
13
votes
2answers
11k views

What's the difference between MariaDB and MySQL?

What's the difference between MariaDB and MySQL? I'm not very familiar with both. I'm primarily a front end developer for the most part. Are they syntactically similar? Where do these two query ...
13
votes
6answers
6k views

Isn't SQLite a bit underestimated? [closed]

Before I ask the question, let me first describe my thoughts about SQLite. I happen to like tools that are small, fast and, more importantly, have only the really necessary functionality. That's why ...
13
votes
8answers
3k views

What qualifies “too many database requests” in code?

This is a discussion myself and some of my colleagues are having and thought I'd come out here and see what if there's a general consensus on it. It basically comes down to the following 2 opinions ...
12
votes
5answers
1k views

How come the computer doesn't have to read the entire table when the column is indexed? [duplicate]

Let's say a table with two columns has 100 quadrillion records. And I want to find a record that has column #2 equal something. If column #2 is indexed it returns the result immediately, but if it's ...
12
votes
8answers
2k 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(*): If ...
12
votes
6answers
2k views

In plain English, what is a database index most similar to? [duplicate]

Setup: Suppose you are teaching an introduction to Databases class, the students are CS students that have a working knowledge of tree structures, how they can speed up searches, and have probably ...
12
votes
5answers
766 views

How to avoid violating the SRP in a class to manage caching?

Note: The code sample is written in c#, but that shouldn't matter. I've put c# as a tag because I can't find a more appropiate one. This is about the code structure. I'm reading Clean Code and trying ...
12
votes
5answers
1k views

For an ORM supporting data validation, should constraints be enforced in the database as well?

I have always applied constraints at the database level in addition to my (ActiveRecord) models. But I've been wondering if this is really required? A little background I recently had to unit test a ...
12
votes
5answers
3k views

Indexing a database

I am not so familiar with databases and now I am trying to understand the indexing mechanism. From what I know, in a RDBMS, indexing on a column makes searching by that column faster. This is also ...
12
votes
7answers
12k views

Best practices to follow with database indexes [closed]

What are some DOs and DONTs for improving database performance using index? A DO would be a case in which an index should be created, or another indexes related tip that will improve performance. A ...
12
votes
4answers
476 views

Database design - Store state or compute state every time?

Let's say I have a relational database application and a "user" object and a "message" object. Now I want to show the number of unread messages to this user. What's the best way to archive this? Do I ...
12
votes
3answers
2k views

General thought process for “How would you build this website/app” interview questions [closed]

I've collected a bunch of interview questions like "Describe how you would design a photo album application", "Describe how you would design this particular feature of this particular website" (e.g. ...
12
votes
7answers
880 views

Whats the best way to determine when it is appropriate to use a database?

I began my programming career in web development using PHP and MySQL. I got quite accustomed to utilizing db for storage of most dynamic data as well as some setting/parameter data. Sometimes there ...
12
votes
2answers
3k views

Is inline SQL still classed as bad practice now that we have Micro ORMs?

This is a bit of an open ended question but I wanted some opinions, as I grew up in a world where inline SQL scripts were the norm, then we were all made very aware of SQL injection based issues, and ...
12
votes
6answers
9k views

HTTP Session or Database approach

I am confused a little as what should be my approach, Working on a design of shopping cart and i need to store shopping cart either in session or in database but not sure which approach would be ...
12
votes
4answers
1k views

What would you think about a new Java persistence tool, that's not really an ORM? [closed]

Persistence in Java Over the past years, I have gathered experience in the field of persistence abstraction in Java, using concepts such as EJB 2.0, Hibernate, JPA and home-grown ones. They seemed to ...
12
votes
1answer
305 views

Can domain models in the database be a sustainable solution?

I just started at a new job as a database developer for a medium-small sized, company based on Microsoft-technology. I noticed early on how much practices deviate from what I've been taught at school ...
12
votes
3answers
880 views

Does ORM promote database de-normalisation?

Doctrine and Propel both make use of single and concrete table inheritance to map object relationships. The former sees all possible fields in the class tree mapped to a single table - whereas the ...
11
votes
10answers
946 views

How could RDBMSes be considered a fad?

Completing my Computing A-level in 2003 and getting a degree in Computing in 2007, and learning my trade in a company with a lot of SQL usage, I was brought up on the idea of Relational Databases ...
11
votes
11answers
1k views

Is continuous creation and deletion of tables a sign of an architectural flaw?

Recently I had a discussion with a developer who mentioned that during program development, they routinely create and delete tables and columns on a regular basis while working on new features and ...
11
votes
3answers
2k views

How to create better OO code in a relational database driven application where the database is poorly designed

I am writing a Java web application that consists mainly of a bunch of similar pages in which every page has several tables and a filter that applies to those tables. The data on these tables comes ...
11
votes
3answers
16k views

Why to use web services instead of direct access to a relational database for an android app?

I searched on the web how to access in an efficient manner to a central database at a remote location and I met suggestions to use web services instead direct access (i.e. JDBC etc ) to a database.I ...
11
votes
2answers
1k views

Why store flags/enums in a database as strings instead of integers?

I've been browsing SQL dumps of some famous CMSes, including Drupal 7, Wordpress (some quite very old version), and some custom application based on Python. All of these dumps contained data with ...
11
votes
3answers
2k views

what are the best tips for storing images in a database?

Is it appropriate to store the image files in the database? Or it would be better to store only the path of the file in the database, while keeping the file itself on the server? Are there any other ...
11
votes
4answers
11k views

Database History Table / Tracking Table

Currently I want to structure a tracking/history table like this: PrimaryKey - ID OtherTableId - fk fieldName - name of the field its tracking OldValue NewValue UserName CreateDateTime So ...
11
votes
2answers
3k views

Will B-Trees and Other Data Structures Become Obsolete With The Advent of Solid State Drives?

Many (perhaps most?) database applications today use B-Trees and variations to store data, because this data structure optimizes the read, write and seek operations on a hard disk (and these ...
11
votes
5answers
1k views

How do I know my data is relational or object oriented in nature?

Just read these lines- If your data is object in nature, then use object stores ("NoSQL"). They'll be much faster than a relational database. If your data is relational in nature, the ...
11
votes
4answers
942 views

Staying OO and Testable while working with a database

What are some OOP strategies for working with a database but keeping things unit testable? Say I have a User class and my production environment works against MySQL. I see a couple possible ...
11
votes
5answers
4k views

Is there any reason to use VARCHAR sizes rounded to a 128/256/4096 byte offset?

In database schema's, I often notice VARCHAR sizes are rounded to the byte offsets 128/256 or 4096. I've done it before as well, and the idea behind it was probably something with efficiency. ...
11
votes
1answer
7k views

Dynamic form builder forms and database design? [closed]

Say your users can create their own web-based forms (textboxes, selects, etc) and publish them on the web for their users to fill out. Does anyone have a resource or any advice on how to architect ...
11
votes
3answers
11k views

Why aren't Object Oriented databases used as much as Relational Databases? [closed]

I have come across many relational database management systems (RDBMS). But recently I used hibernate which made me start wondering why Object Oriented databases aren't more popular. If object ...
11
votes
4answers
354 views

Can I use the database structure of an open source project?

I found a database structure for a CMS system and I want to copy it with the EF that this database is done in, is it OK to copy the database structure of open source software which is under GNU v2 ...
11
votes
2answers
6k views

Why NoSQL over SQL? [duplicate]

Possible Duplicate: When would someone use MongoDB (or similar) over traditional RDMS? How well the SQL and NoSQL go head-to-head. I read somewhere that SQL databases are not well for data ...
11
votes
3answers
3k views

How to handle Real Time Data from a database perspective?

I have an idea in mind, but it still confuses me the database area. Imagine that I want to show real time data, and using one of the latest browser technologies (web sockets - even using older ...
11
votes
2answers
753 views

Should I keep email addresses as plaintext in database?

It's clear to everyone (I hope) that storing passwords without at least salting/hashing them is a terrible idea. What about emails? Let's say you keep the subscription email address, if you encrypt ...