4.3.8.1 Initial Example

A simple RDML program to list off the transactions file and also show full transaction and state descriptions fields might be coded like this:

GROUP_BY   NAME(#TRANS) FIELDS(#TRANNUM #TRANDATE #TRANTIME

           #TRANTYPE #TRANDESC #TRANUSER #TRANSTATE #STATDESC)

 

SELECT     FIELDS(#TRANS) FROM_FILE(TRANS)

FETCH      FIELDS(#TRANS) FROM_FILE(STATES) 

           WITH_KEY(#TRANSTATE)

FETCH      FIELDS(#TRANS) FROM_FILE(TRNTYP) 

           WITH_KEY(#TRANTYPE)

UPRINT     FIELDS(#TRANS)

ENDSELECT

 

If file TRANS contained 10,000 records this RDML program would do (10,000 + 10,000 + 10,000) = 30,000 database accesses.

However, by using a working list, or the KEEP_LAST parameter on the FETCH commands, the speed of this program can be improved considerably.