Technically, it's impossible for installer to create database for you UNLESS you provide it with username and password of the superuser (e.g. root).
After installation, it stores the superuser name and password in a config file to remember them later whenever it wants to connect to the database. This is bad security, it leaves your superuser information out somewhere. Due to a security bug in ANY application running under apache, someone could be able to read your config file and steal your superuser information.

Drupal strives for ease of use but without affecting security.

On 10/11/06, Drupal Indonesia <support@drupal-id.com > wrote:
Hi,

I just try 5.x CVS version and very sad that the installation procedure can't
create the Database for me! Unlike Joomla, this is very sad.
Does core dev have plan to make it better (easier)?

Regards.