0
votes
1answer
154 views

MongoDB: Replicate data in documents vs. “join”

Disclaimer: This is a question derived from this one. What do you think about the following example of use case? I have a table containing orders. These orders has a lot of related information ...
16
votes
4answers
2k views

Why many designs ignore normalization in RDBMS?

I got to see many designs that normalization wasn't the first consideration in decision making phase. In many cases those designs included more than 30 columns, and the main approach was "to put ...
6
votes
8answers
2k views

Why can't SQL return joined tables in a nested format?

For example, say I want to fetch a User and all of his phone numbers and email addresses. The phone numbers and emails are stored in separate tables, 1-user to many phones/emails. I can do this quite ...
6
votes
2answers
883 views

In what order are rows fetched absent ORDER BY clause?

One programmer is testing and comparing the same application which uses the same database structure, and the same data, only in two separate databases, one with Oracle 8 and one with Oracle 9. The ...
4
votes
3answers
334 views

Rule of thumb for field sizes

What VARCHAR sizes should be used for first and last names, phone numbers (preferably international), email adresses, urls, dictionary words and file names? Edit: Zapped the introductory phrase to ...
13
votes
5answers
1k views

Why is filesystem preferred for logs instead of RDBMS?

Question should be clear from its title. For example Apache saves its access and error logs in files instead of RDBMS no matter on how large or small scale it is being utilized. For RDMS we just have ...
36
votes
11answers
2k views

Why don't relational databases support returning information in a nested format?

Suppose I'm building a blog that I want to have posts and comments. So I create two tables, a 'posts' table with an autoincrementing integer 'id' column, and a 'comments' table that has a foreign key ...