Foxpro String Variable combination in Forloop - sql

Question

As in title, there is an error in my first code in FOR loop: Command contains unrecognized phrase. I am thinking if the method string+variable is wrong.
ALTER TABLE table1 ADD COLUMN prod_n c(10)
ALTER TABLE table1 ADD COLUMN prm1 n(19,2)
ALTER TABLE table1 ADD COLUMN rbon1 n(19,2)
ALTER TABLE table1 ADD COLUMN total1 n(19,2)
There are prm2... until total5, in which the numbers represent the month.
FOR i=1 TO 5
REPLACE ALL prm+i WITH amount FOR LEFT(ALLTRIM(a),1)="P" AND
batch_mth = i
REPLACE ALL rbon+i WITH amount FOR LEFT(ALLTRIM(a),1)="R"
AND batch_mth = i
REPLACE ALL total+i WITH sum((prm+i)+(rbon+i)) FOR batch_mth = i
NEXT
ENDFOR
Thanks for the help.

Answer 1

There are a number of things wrong with the code you posted above. Cetin has mentioned a number of them, so I apologize if I duplicate some of them.
PROBLEM 1 - in your ALTER TABLE commands I do not see where you create fields prm2, prm3, prm4, prm5, rbon2, rbon3, etc.
And yet your FOR LOOP would be trying to write to those fields as the FOR LOOP expression i increases from 1 to 5 - if the other parts of your code was correct.
PROBLEM 2 - You cannot concatenate a String to an Integer so as to create a Field Name like you attempt to do with prm+i or rbon+1
Cetin's code suggestions would work (again as long as you had the #2, #3, etc. fields defined). However in Foxpro and Visual Foxpro you can generally do a task in a variety of ways.
Personally, for readability I'd approach your FOR LOOP like this:
FOR i=1 TO 5
* --- Keep in mind that unless fields #2, #3, #4, & #5 are defined ---
* --- The following will Fail ---
cFld1 = "prm" + STR(i,1) && define the 1st field
cFld2 = "rbon" + STR(i,1) && define the 2nd field
cFld3 = "total" + STR(i,1) && define the 3rd field
REPLACE ALL &cFld1 WITH amount ;
FOR LEFT(ALLTRIM(a),1)="P" AND batch_mth = i
REPLACE ALL &cFld2 WITH amount ;
FOR LEFT(ALLTRIM(a),1)="R" AND batch_mth = i
REPLACE ALL &cFld3 WITH sum((prm+i)+(rbon+i)) ;
FOR batch_mth = i
NEXT
NOTE - it might be good if you would learn to use VFP's Debug tools so that you can examine your code execution line-by-line in the VFP Development mode. And you can also use it to examine the variable values.
Breakpoints are good, but you have to already have the TRACE WINDOW open for the Break to work.
SET STEP ON is the Debug command that I generally use so that program execution will stop and AUTOMATICALLY open the TRACE WINDOW for looking at code execution and/or variable values.

Answer 2

Do you mean you have fields named prm1, prm2, prm3 ... prm12 that represent the months and you want to update them in a loop? If so, you need to understand that a "fieldName" is a "name" and thus you need to use a "name expression" to use it as a variable. That is:
prm+i
would NOT work but:
( 'pro'+ ltrim(str(m.i)) )
would.
For example here is your code revised:
For i=1 To 5
Replace All ('prm'+Ltrim(Str(m.i))) With amount For Left(Alltrim(a),1)="P" And batch_mth = m.i
Replace All ('rbon'+Ltrim(Str(m.i))) With amount For Left(Alltrim(a),1)="R" And batch_mth = m.i
* ????????? REPLACE ALL ('total'+Ltrim(Str(m.i))) WITH sum((prm+i)+(rbon+i)) FOR batch_mth = i
Endfor
However, I must admit, your code doesn't make sense to me. Maybe it would be better if you explained what you are trying to do and give some simple data with the result you expect (as code - you can use FAQ 50 on foxite to create code for data).