How to fix Dynamic Query error for progress 4gl? - openedge

Question

I am new to progress 4GL. I have written logic for buffer by adding multiple tables into a single query and finding the records from another table by using table field names. I am not sure why I am getting errors. Please help to change the logic
DEFINE VARIABLE ix AS INTEGER NO-UNDO.
DEFINE VARIABLE qh AS HANDLE NO-UNDO.
DEFINE VARIABLE bh AS HANDLE NO-UNDO.
DEFINE VARIABLE fh AS HANDLE NO-UNDO EXTENT 10.
DEFINE VARIABLE cQuery AS CHARACTER NO-UNDO.
CREATE BUFFER bh FOR TABLE "Customer, Invoice".
CREATE QUERY qh.
ASSIGN
cQuery = "FOR EACH Customer NO-LOCK, EACH Invoice WHERE Invoice.Cust-Num = Customer.Cust-
Num NO-LOCK: ".
qh:SET-BUFFERS(bh).
qh:QUERY-PREPARE(cQuery).
qh:QUERY-OPEN().
qh:GET-FIRST().
/* Field Invoice.Cust-Num is already defined in cQuery*/
FIND Order WHERE Order.Cust-Num = Invoice.Cust-Num NO-LOCK NO-ERROR.
IF NOT AVAILABLE Order THEN DO:
FIND Ref-Call WHERE Ref-Call.Cust-Num = Invoice.Cust-Num NO-LOCK NO-ERROR.
DISPLAY Ref-Call.Cust-Num.
END.
qh:QUERY-CLOSE().
bh:BUFFER-RELEASE().
DELETE OBJECT bh.
DELETE OBJECT qh.

Answer 1

Looking at the field names, you're using the classic Sports Database for your training. There's a "newer" Sports2000 demo database with a little bit more of data that might be worth playing with.
There are multiple issues in that program.
First, you cannot define a single dynamic buffer for two tables (Customer, Invoice). This would be causing an error at runtime. You need to:
DEFINE VARIABLE bh1 AS HANDLE NO-UNDO.
DEFINE VARIABLE bh2 AS HANDLE NO-UNDO.
CREATE BUFFER bh1 FOR TABLE "Customer".
CREATE BUFFER bh2 FOR TABLE "Invoice".
and then
qh:ADD-BUFFER(bh1).
qh:ADD-BUFFER(bh2).
The second issue (your compile error), is because the compiler does not see that you're accessing the table Invoice already. bh2 will only at runtime be known to be a buffer for the Invoice table. So you need to access the Cust-Num field dynamically:
FIND Order WHERE Order.Cust-Num = bh2::Cust-Num NO-LOCK NO-ERROR.
Note: You're accessing a single Order by the Cust-Num of the invoice here - I assume, you want to do something like accessing the Order by the Invoice's Order-Num field. That would be a logical mistake, not a syntax error.
However, nothing in your program justifies the need for a dynamic query. That just adds in this case unneeded complexity. You program is not yet iterating the records in the dynamic-query qh - but I assume that's the goal. So this simple static FOR EACH block does the same:
FOR EACH Customer NO-LOCK, EACH Invoice WHERE Invoice.Cust-Num = Customer.Cust-
Num NO-LOCK:
FIND Order WHERE Order.Cust-Num = Invoice.Cust-Num NO-LOCK NO-ERROR.
IF NOT AVAILABLE Order THEN DO:
FIND Ref-Call WHERE Ref-Call.Cust-Num = Invoice.Cust-Num NO-LOCK NO-ERROR.
DISPLAY Ref-Call.Cust-Num.
END /* NOT AVAILABLE */.
END. /* FOR EACH */
Lastly, here:
DELETE OBJECT bh.
DELETE OBJECT qh.
DELETE OBJECT statements belong by their nature into a FINALLY
block.
You need to check validity of the handles before deleting
them:
FINALLY:
IF VALID-HANDLE (bh1) THEN DELETE OBJECT bh1.
IF VALID-HANDLE (bh2) THEN DELETE OBJECT bh2.
IF VALID-HANDLE (qh) THEN DELETE OBJECT qh.
END.

Answer 2

Here is a working example - my changes to your code can generally be identified by being in lower case.
DEFINE VARIABLE qh AS HANDLE NO-UNDO.
DEFINE VARIABLE bhc AS HANDLE NO-UNDO.
DEFINE VARIABLE bhi AS HANDLE NO-UNDO.
DEFINE VARIABLE cQuery AS CHARACTER NO-UNDO.
CREATE BUFFER bhc FOR TABLE "Customer".
create buffer bhi for table "Invoice".
CREATE QUERY qh.
cQuery = "FOR EACH Customer NO-LOCK,"
+ "EACH Invoice WHERE Invoice.CustNum = Customer.CustNum no-lock".
qh:SET-BUFFERS(bhc,bhi).
qh:QUERY-PREPARE(cQuery).
qh:QUERY-OPEN().
do while qh:get-next().
message bhc::CustNum bhi::InvoiceNum.
FIND Order WHERE Order.CustNum = bhi::CustNum NO-LOCK NO-ERROR.
IF NOT AVAILABLE Order THEN DO:
FIND RefCall WHERE RefCall.CustNum = bhi::CustNum NO-LOCK NO-ERROR.
if available RefCall then
message RefCall.CustNum.
END.
end.
finally:
DELETE OBJECT bhc no-error.
DELETE OBJECT bhi no-error.
DELETE OBJECT qh no-error.
end finally.
Watch the example run in ABLdojo.