Advice on managing databases

Sevenupcan

While I can create a database and set up different applications like WordPress and Vanilla, I don't really know much about databases. At the moment I'm afraid that the way I am managing my database may be bad practice.

I currently have several sites each with a separate database for each application. For example...

slogmeat.com --- exampledb_slogmeat_blog
slogmeat.com --- exampledb_slogmeat_forum
dmvu.com --- exampledb_dmvu_blog
dmvu.com --- exampledb_dmvu_forum

and so on.

What I'd like to know is should all these databases be set as one database? For example...

slogmeat.com --- exampledb_blog (but with prefix of slogmeat_)
dmvu.com --- exampledb_blog (but with prefix of dmvu_)

or

slogmeat.com --- exampledb_slogmeat (but with prefix blog_ and forum_)
dmvu.com --- exampledb_dmvu (but with prefix blog_ and forum_)

Hope that what I'm saying is clear. Any help would be greatly appreciated as I am unfamiliar with how databases and MySQL actually works and can't find any beginner resources on the subject.

Bergamot

Unless your host sets a limit on the number of databases you can use, it's best to separate them so you don't even have to worry about namespace conflicts. The only exception I can think of is if they share tables, and the app is only designed to use one database (like vanilla); then it makes sense to keep them in the same db.

Sevenupcan

Thanks for the help, I'll keep doing what I normally do then. One more question I have is when should I have different database users? I take it that only applies when someone else needs to access the database?

Bergamot

I have a different user for each db, so if a hacker gets access to one, the rest aren't hosed. I'm not really an expert in DB security though.