Database

First, you need to set the connection config:

$config['db.host'] = 'localhost';
$config['db.name'] = 's-company-project';
$config['db.user'] = 'stage';

$config['db.prefix'] = 'tbl_';

$secret['db.pass'] = ['type' => 'str'];

As the password is stored via the secret helper, run either of these:

./cli --secret=check

./cli --install

You can get access to the database object though the helper function:

$db = db_get();

Alternative connections

If you need to connect to a different database, use the configuration:

$config['db.old.host'] = 'localhost';
$config['db.old.name'] = 's-company-project';
$config['db.old.user'] = 'stage';

$secret['db.old.pass'] = ['type' => 'str'];

Then access the database object via:

$db_old = db_get('old');