Reading (EVAL) a file in RPG
Hi,
I'm a newbie when it comes to RPG and I couldn't find anything when searching.
So this is what I need. I'm adding a record to a file but don't want any duplicates so I guess I need s simple RPG proogram that takes in one parm, reads a file (with one field) and if it comes across an exact match, I need to be notified that the record exists.
From there I should be able to modify a CL to alert me if that the record was added, deleted... etc.
Thanks for any help
bgg
Software/Hardware used:
I'm a newbie when it comes to RPG and I couldn't find anything when searching.
So this is what I need. I'm adding a record to a file but don't want any duplicates so I guess I need s simple RPG proogram that takes in one parm, reads a file (with one field) and if it comes across an exact match, I need to be notified that the record exists.
From there I should be able to modify a CL to alert me if that the record was added, deleted... etc.
Thanks for any help
bgg
Software/Hardware used:
ASKED:
September 14, 2010 8:29 PM
UPDATED:
September 15, 2010 5:43 PM
Answer Wiki:
in your file DDS define the file with a UNIQUE key
in your RPG
/Free
Chain (key1 : key2 : Etc) FileName;
if Not %Found;
Write record;
EndIf;
/End-Free
Or
c KEY klist
c kfld key1
c kfld key2
c kfld etc
c KEY chain file 99
c if *in99 = *On
c write record
c endif
-Sarge
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If you don’t want duplicate records, define the file as uniquely keyed. Then when you attempt to insert a duplicate, your program will be signaled of the error condition.
You can certainly code the process that you asked about, but it’s a long way around to get what the system will give you for little effort.
Tom
Tom’s suggestion is the best answer, because by putting a UNIQUE key on the file, you never have to worry about how the file is updated. If you do a CPYF or DBU, or DFU, it will ALWAYS stop the process and not allow records with duplicate keys.