For MSSQL make all connection attributes optional.
Handle differing DB connection params based on driver used.
connection can be made via ODBC DSN or server/hostname
username/password can be embedded in DSN definition or simply
omitted and single-signon will be attempted.
When using charset in buildDsn, not all variables are set on the server side. That leads to MySQL assuming latin1 charset and errors with Cyrillic, for example (I figured out the letter 'И', capital breaks the things).