UniBasic Commands Reference - Rocket Software

READFWD
Syntax
READFWD dyn.array.var [FROM file.var] [ON ERROR statements] {THEN
statements [END] | ELSE statements [END]}
Description
The first READFWD command retrieves the alternate key set by SETINDEX, and
then each subsequent READFWD retrieves the next alternate key value in the index.
UniData reads the corresponding record into a dynamic array, and then assigns the
record ID to the @ID variable.
Note: This command does not check for locks. If you are operating in a multiuser
environment, you must use record locks to prevent more than one user from accessing
the same record at the same time. For more information about the UniBasic record
locking, see Developing UniBasic Applications.
Using this command in a loop, a UniBasic program retrieves records in ascending
order based on an indexed attribute.
Before executing READFWD, you must set a pointer to an alternate key value with
the SETINDEX command. The SETINDEX parameters BUFFER.KEYS and
VALIDATE.KEY determine, respectively, whether the buffering mechanism is used
and whether keys are validated when READFWD executes. For details, see
SETINDEX.
READFWD sets the STATUS function return value to 10 if UniBasic detects a
duplicate alternate index key value and you have executed the ECL command
DUP.STATUS ON during the current session.
1-610 UniBasic Commands Reference