Re: Timestamp vs Date/time Decimal fields, Overhead in RPG programs...

[CRPence <CRPbottle@xxxxxxxxx>]

  The original implementation of date\time and timestamp had the 
database always converting a first time from internal [i.e. integer] 
form to the external character string when read by the RPG; a full 
26-bytes for a TIMESTAMP field, for example.  Thus when any function 
against the date-related field was requested, the strings would have 
to be converted a second time, into the internal form in order to 
perform any date arithmetic & comparisons, then those integers would 
have to be converted a third time into strings when requesting to 
place the updated values in the database, and finally the database 
would convert those strings a fourth time to the internal form for 
the actual record in the database file.

  As I understood, that implementation had changed such that the 
RPG could & would ask the database to return the data in the 
internal form for those data types, and perform the conversion into 
the string representation only when requested.  Thus those date 
related data types should work much more like the numeric types with 
editing, except instead of %edit_ BIFs, using date\time related 
BIFs.  Any calculated or unchanged value in internal form can then 
be passed back directly to the database in the same internal form, 
thus avoiding any conversion from string to internal form by the 
database update or write; just as it was on the read.

  Except if made available by UDF to the database, the functions 
which might\could be used to treat the decimal values as date\time 
[beyond just presentation to give the appearance that the decimal 
values are date\time] are not available to the database.  Thus to 
utilize date\time\timestamp in the database without the RPG [e.g. in 
SQL], define the column\field data with the actual date\time\TS data 
types to directly enable the various date\time related scalar 
functions, arithmetic, & comparisons.

Regards, Chuck

George Lopez wrote:
> From what I heard from Bob Cozzi years many years ago there is a 
> disadvantage using timestamp field in physical file instead of
> the tried and true date and time decimal fields in terms of speed
> if you are doing mass update of those fields in an RPG progam?
> Or is that not true anymore?