[DOUBT] Database instance access

Hi everyone!

I'm a brazilian student and I'm developping with my professor a new tool for the moodle. It's a simple block with a link to an external code. In my external code I have a script that has the connection configurations (user, password, database name...) and the functions for connect with the database. In that way I can execute my queries in the moodle's db.

The question is: How do I get the moodle's instance connection (if is possible) to execute my queries and no need anymore to configure a external script to get this access?

I read the Data manipulation API, but I don't understood very well how to use it.

I expect that you understand my doubt ;)

Thanks,
Regards.