[R] rodbc windows doesn't find dsn

[Jack Tanner]

Prof Brian Ripley wrote:
>      'odbcConnect' establishes a connection to the dsn, and
>      'odbcDriverConnect' allows a more flexible specification via a
>      connection string.  'odbcConnect' uses the connection string
>      '"DSN=dsn;UID=uid;PWD=pwd"'. 

The point here seems to be that odbcConnect is meant to provide a useful 
default, and odbcDriverConnect allows one to override that default. 
Could somebody shed some light on why '"DSN=dsn;UID=;PWD="' is 
considered a more useful default than '"DSN=dsn;"'?