Are all 'dextrorotatory' sugars in biology actually 'd' or '+' in chirality?
Dextrorotatory = d = (+). Levorotatory = l = (-). These terms describe the absolute sense of rotation in an optically active substance.
D and L are older terms for the sense of chirality that can be traced back to dextro- or levorotation of glyeraldehyde. The actual compound may have the same or opposite sense of rotation, but the assignment is determined by analogy. (Cf. Fisher/Rosanoff).
R and S describe absolute stereochemistry of a center, so a specific molecule with multiple chiral centers cannot be sufficiently described with a single R or S, but require one for each stereocenter. This designation is part of the more modern (and widely accepted) Cahn-Ingold-Prelog system, which has largely been adopted by IUPAC.
Note that while D and L might be sufficient to describe a sugar, anything more complicated than a 3-carbon aldose or 4-carbon ketose is not likely to be properly described with a single R or S because there are multiple stereocenters.