Database error--can't access backend

[Chouette]

Hi,

I wrote previously about losing my homepage when I deleted an admin. I guess it was connected to her in some way.

I haven't heard any response yet to my query about what to do to get it back.

BUT I'm posting again because due to what I did, I now can't access the backend of my WP site, i.e., through the normal login page.

I get the following message:

Error establishing a database connection

Can anyone shed light on this for me and possibly provide a solution?

I have complete backups--the site and the database.

Can I just FTP the database and be completely restored--access and homepage?

Or maybe should I FTP the complete files from the last backup?

Any help is appreciated.