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Questions tagged [database]

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

16
votes
4answers
2k 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 approaches,...
21
votes
3answers
8k views

Store images in the database, or in files with a database link?

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 ...
25
votes
6answers
5k views

Databases and Unit/Integration Testing

I have had a discussion with someone about unit/integration testing with web applications and I have a disagreement about 1 core idea. The issues is that the person I am talking to think that the ...
25
votes
5answers
21k views

What is the difference between all-static-methods and applying a singleton pattern? [duplicate]

I am making a database to store information about the users of my website (I am using stuts2 and hence Java EE technology). For the database I'll be making a DBManager. Should I apply singleton ...
129
votes
9answers
95k views

When would someone use MongoDB (or similar) over a Relational DBMS?

I'm a bit confused about the whole NoSQL thing and such. When would you choose to use something like MongoDB over something like Oracle or MySQL? I don't really understand the "difference" as far as ...
98
votes
9answers
42k views

How much business logic should the database implement?

I've worked in some projects where most of the business logic was implemented on the database (mostly through stored procedures). On the other side, I've heard from some fellow programmers that this ...
91
votes
2answers
120k views

Creating database connections - Do it once or for each query?

At the moment I create a database connection when my web page is first loaded. I then process the page and run any queries against that conection. Is this the best way to do it or should I be creating ...
40
votes
4answers
18k views

Achieving Zero Downtime Deployment

I am trying to achieve zero downtime deployments so I can deploy less during off hours and more during "slower" hours - or anytime, in theory. My current setup, somewhat simplified: Web Server A (....
60
votes
15answers
17k views

Is there any reason not to go directly from client-side Javascript to a database?

Possible Duplicate: Writing Web “server less” applications So, let's say I'm going to build a Stack Exchange clone and I decide to use something like CouchDB as my backend store. If I use their ...
27
votes
1answer
19k views

What is a realistic, real-world, maximum size for a SQLite database?

According to this article on Appropriate Uses For SQLite it says that, while SQLite is limited to 140 terabytes, a client/server RDBMS may work better: An SQLite database is limited in size to 140 ...
188
votes
13answers
139k views

Why use a database instead of just saving your data to disk?

Instead of a database I just serialize my data to JSON, saving and loading it to disk when necessary. All the data management is made on the program itself, which is faster AND easier than using SQL ...
31
votes
6answers
35k views

Should I use one database per application or share a single database amongst multiple applications [closed]

I have multiple applications some that use data from the same sources. Is it best practice (or what are the pros/cons) to: leave the data in databases shared by multiple applications saves space as ...
22
votes
7answers
6k views

Safely fixing production database data

Bugs happen and sometimes data has to be fixed in production. What is the safest way to go about this from a big company standpoint? Are there tools that can help? Here are some considerations driving ...
11
votes
2answers
5k views

How do you handle database change deployments?

We have been discussing database deployment techniques today, having had a couple of recent failures in our current process and having seen situations where we would like to roll back a deployment but ...
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 ...
183
votes
17answers
50k views

Is it good practice to always have an autoincrement integer primary key?

In my databases, I tend to get into the habit of having an auto-incrementing integer primary key with the name id for every table I make so that I have a unique lookup for any particular row. Is this ...
46
votes
8answers
15k views

Storing a re-orderable list in a database

I'm working on a wishlist system, where users can add items to their various wishlists, and I plan to allow users to re-order the items later on. I am not really sure about the best way to go about ...
39
votes
3answers
22k views

Should I use a config file or database for storing business rules?

I have recently been reading The Pragmatic Programmer which states that: Details mess up our pristine code—especially if they change frequently. Every time we have to go in and change the code to ...
47
votes
6answers
5k views

Business logic: Database vs code [duplicate]

I'm a student of systems engineering, and all my teachers and friends (that actually work in the area) say that it is better to have as much logic as possible implemented in the database (queries, ...
51
votes
13answers
11k 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 ...
19
votes
4answers
3k 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 ...
13
votes
9answers
10k views

How much database access should developers have? [closed]

So I've worked in many different workplaces as a developer and my level of access to the database has been varied. I typically don't have production db access. Most of the time I have access to the ...
6
votes
4answers
3k views

When is it necessary to use ORM tools? [closed]

I was raised in a part of web developmentland where the creation of websites is mostly synonymous with Wordpress, FTP, Joomla, and procedural code, instead of things like TDD, A/B testing, Doctrine, ...
11
votes
1answer
8k views

Log to file or to database table?

I'm developing a web application which uses MS SQL for various data: including users, user accounts, user licenses, license prices, invoices. I need to log users' real-time usage of the system, and ...
5
votes
8answers
2k views

How do you decide between putting the code in the database or putting the code in the application? [closed]

For the sake of argument: Let's assume the application we are building is an amortization schedule. Let's also assume that the database has a table called tblAmortizationPayments that stores the ...
3
votes
3answers
1k views

database migration: upgrade schema deployed on client machines

I'm working on an application, which when deployed is installed locally on client machines, and uses a local database server. Stupidly, I didn't plan for schema changes -- and now it needs to change. ...
11
votes
3answers
4k views

Unit testing vs Integration Testing [duplicate]

What is the difference between unit testing and integration testing when it come to web development (where 90-95% of the code relies on a database)? One thing I here all the time is that unit testing ...
6
votes
2answers
12k views

Database model for keeping track of likes/shares/comments on blog posts over time

My goal is to keep track of the popular posts on different blog sites based on social network activity at any given time. The goal is not to simply get the most popular now, but instead find posts ...
6
votes
4answers
2k views

How to add image support to client-server database application?

I have an architectural question about a project that I am working on. Currently it is a simple .NET C# application that runs on several client machines, and communicates with a central MySQL server ...
1
vote
1answer
1k views

js spa rest backend business logic vs presention logic

I am very confused about what should a SPA's REST backend do and expose. In most blog posts and books I read they depict the backend pretty much like a direct access to the DB, practically CRUD ...
92
votes
3answers
48k views

How is localStorage different from indexedDB?

localStorage and indexedDB are used for offline storage of data in HTML5. What are their key differences and which one is preferable in what situations?
66
votes
8answers
48k views

Why would you store an enum in DB?

I've seen a number of questions, like this, asking for advice on how to store enums in DB. But I wonder why would you do that. So let's say that I have an entity Person with a gender field, and a ...
95
votes
10answers
50k views

Why is “Select * from table” considered bad practice

Yesterday I was discussing with a "hobby" programmer (I myself am a professional programmer). We came across some of his work, and he said he always queries all columns in his database (even on/in ...
57
votes
11answers
5k views

Database source control

Should database files(scripts etc.) be on source control? If so, what is the best method to keep it and update it there? Is there even a need for database files to be on source control since we can ...
29
votes
4answers
17k views

How to prevent race conditions in a web application?

Consider an e-commerce site, where Alice and Bob are both editing the product listings. Alice is improving descriptions, while Bob is updating prices. They start editing the Acme Wonder Widget at the ...
14
votes
4answers
16k 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 ...
26
votes
3answers
15k 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 ...
14
votes
2answers
9k 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 that ...
13
votes
5answers
12k views

When should use of database be preferred over parsing data from a text file?

I was making a Python program to measure the growth of codereview.SE. My approach was to get the "Site stats" shown on the front page and store them on my hard drive. I plan to do this once every day. ...
9
votes
6answers
11k views

Is MongoDB the right choice in my case? [closed]

I'm going to build my first real project in Rails that consist in a web app made of 3 main parts: The static part where no database is used The User registration part which will require a database ...
13
votes
7answers
4k 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 ...
15
votes
4answers
2k views

Why do relational databases only accept SQL queries?

As far as I know, most relational databases do not offer any driver-level API for queries, except a query function which takes an SQL string as an argument. I'm thinking how easier it would be if one ...
10
votes
5answers
6k views

How to decide between storage formats and what are example use cases for some of them?

We have different ways to store program data (save files in games, employee databases, program configuration etc.): Plain text (think .ini and .conf) XML Databases (MySQL, SQLite...) .zip and similar ...
7
votes
3answers
2k views

How to manage database schema changes in open source project releases

I manage an open source PHP/MySQL web application used by a few K-12 schools and some colleges. I'm also the project's only developer. While it used to be little more than a source download of an ...
0
votes
1answer
1k views

Search for object in loop or query? Who has better performance?

I have a DB that stores some complex objects of my app. When my app starts I load the objects into list and store them on the RAM. But sometimes I would like to search for an objects that fulfills ...
8
votes
4answers
5k views

Is storing a list of strings in single database field a bad idea? Why?

Recently, I started to work on some legacy system. People that developed it, came to an idea to store list of strings in single field of database table. Lets say that it is an identifier for object ...
5
votes
3answers
632 views

Establishing an API to provide end-user apps/scripts access to multiple types of databases

Question and Context I am currently working on a project where the main question is, how do we insert an API between the database and end-users who may develop applications/scripts of their own that ...
4
votes
3answers
1k views

OOP and relational databases [duplicate]

I see a lot of talk in the OOP world about principles and laws such as Open/Close and Loose Coupling, I can understand how they are so high valued, However I seem to have ran into a problem with ...
3
votes
2answers
319 views

Implementing set of processes in a stored procedure or through the code?

I want to know what's the suitable method to implement the following case (best practice). If i make a set of processes like this: select data from set of DB tables. loop on the selected result. ...
2
votes
3answers
440 views

At which point using string-based enums can become a real problem?

This is a direct follower to this question. An answer given to that questions says (my understanding), that nowadays using string-based enums instead of integers isn't a much problem, because hosting ...