This function is
EXPERIMENTAL. The behaviour of this function, the
name of this function, and anything else documented about this
function may change in a future release of PHP without notice. Be
warned and use this function at your own risk.
dbplus_ropen() will open the relation
file locally for quick access without any
client/server overhead. Access is read only and only
dbplus_current() and
dbplus_next() may be applied to the returned
relation.