difference between sy-datum and sy-datlo

data sySY-DATUM and the system fields for the local time zone, that is SY-TIMLO, SY-DATLO, and SY-ZONLO are also reset. SY-DATLO Local date of user, for example 19981129, 19990628.I am a quantitative psychologist with expertise in (1) dynamic modeling, particularly methodologies for handling intensive longitudinal data.