dbConnect-GreenplumDriver-method: Connect to a Greenplum database.
In RGreenplum: Interface to 'Greenplum' Database

Manually disconnecting a connection is not necessary with RGreenplum, but still recommended; if you delete the object containing the connection, it will be automatically disconnected during the next GC with a warning.

## S4 method for signature 'GreenplumDriver'
dbConnect(drv, dbname = NULL, host = NULL,
  port = NULL, password = NULL, user = NULL, service = NULL, ...,
  bigint = c("integer64", "integer", "numeric", "character"))

`drv`	'RGreenplum::Greenplum()'
`dbname`	Database name. If 'NULL', defaults to the user name. Note that this argument can only contain the database name, it will not be parsed as a connection string (internally, 'expand_dbname' is set to 'false' in the call to ['PQconnectdbParams()'](https://www.postgresql.org/docs/9.6/static/libpq-connect.html)).
`host, port`	Host and port. If 'NULL', will be retrieved from 'PGHOST' and 'PGPORT' env vars.
`user, password`	User name and password. If 'NULL', will be retrieved from 'PGUSER' and 'PGPASSWORD' envvars, or from the appropriate line in '~/.pgpass'. See <http://www.postgresql.org/docs/9.6/static/libpq-pgpass.html> for more details.
`service`	Name of service to connect as. If 'NULL', will be ignored. Otherwise, connection parameters will be loaded from the pg_service.conf file and used. See <http://www.postgresql.org/docs/9.6/static/libpq-pgservice.html> for details on this file and syntax.
`...`	Other name-value pairs that describe additional connection options as described at <http://www.postgresql.org/docs/9.6/static/libpq-connect.html#LIBPQ-PARAMKEYWORDS>
`bigint`	The R type that 64-bit integer types should be mapped to, default is [bit64::integer64], which allows the full range of 64 bit integers.