Referencing Fields by Name

[jsplice]

Hello everyone. I'm using a For loop and am trying to reference 8 fields in a neat manner. The fields are:

LCDT01
LCDT02
...
LCDT08

Here is part of the loop:

C For i = 1 to 8
C Move i @LCDField
C MoveL 'LCDT0 ' @LCDField



@LCDField is a 6 character field that is holding the file field name. I want to be able to reference each field inside the loop by using @LCDField so that I don't have to manually check each field. However, I'm not sure if this is possible. Can anyone help with this?

 

[flapeyre]

No, you can't do it that way. RPG does not allow it.

Unless you are writing somrthing that will process any file, I don't understand why you need to do that.

If these fields are all the same length and type, you can declare an array and rename them in the I-specs, and refer to them as the elements of that array.

Feles mala! Cur cista non uteris? Stramentum novum in ea posui!

 

[jsplice]

The fields are actually coming from a data structure that is being passed in as a parm to this procedure. The data structure is externally described on the file, so I can access these fields by their name. Essentially the data structure is holding an entire record that is being passed in. Yes, I know it seems a bit ridiculous to do it this way, but I'm simply following the specs. Thanks for the answer though.

 

[Mercury2]

I think that SQL PREPARE stm could do the trick. Depends on what you want to do next.

 

[jsplice]

I was told by someone that it may be possible to "dynamically determine" the buffer positions and lengths of all the fields in a file and the use those positions to reference the fields. I'm running into the same problem again. I have a procedure that is passed a field name which is the field to be compared between two files or data structures. Is there absolutely no way to do this in RPG-only code?

 

[Mercury2]

Yes, actually it's possible to determine lengths and fields names aso in a file using SQL DESCRIBE and SQLDA (SQL Descriptor Area); however this is not for faint-hearted programmers.

Check out sql Describe and SQLDA in the manual "DB2 Universal Database for iSeries SQL Reference" at

http://publib.boulder.ibm.com/iseries/v5r2/ic2924/info/db2/rbafzmst.pdf

and the examples in the manual "DB2 Universal Database for iSeries SQL Programming with Host Languages" at

http://publib.boulder.ibm.com/iseries/v5r2/ic2924/info/rzajp/rzajpmst.pdf

These manuals are a true treasury for programmers