spec_driver_connect
dbConnect() returns an S4 object that inherits from '>DBIConnection.
This object is used to communicate with the database engine.
DBI recommends using the following argument names for authentication
parameters, with NULL default:
user for the user name (default: current user)
password for the password
host for the host name (default: local connection)
port for the port number (default: local connection)
dbname for the name of the database on the host, or the database file
name
The defaults should provide reasonable behavior, in particular a
local connection for host = NULL. For some DBMS (e.g., PostgreSQL),
this is different to a TCP/IP connection to localhost.