RE: Preparing dynamic SQL and parameter markers

Sorry Jonathon, I guess Vern's reply shot this down...Thanks Vern...

Rob

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx]
On Behalf Of Robert Rogerson
Sent: February 4, 2008 8:37 AM
To: RPG programming on the AS400 / iSeries
Subject: RE: Preparing dynamic SQL and parameter markers

I think you are correct in that a Prepared statement must be used but I
think you do not need the parameter marker.

C Eval wSQL = 'Select SUBSTR(CIFLD, 3, 8) '
+
C 'Into :myVariable '
+
C 'From ' + %Trim(wFileName) + '
' +
C 'Where SUBSTR(CIFLD, 1,
2)=''CI'' ' +
C 'and SUBSTR(CIFLD,19,18)=' +
wQuote +
C MobileNo + wQuote

The parameter markers represent the columns in the table not the host
variables.
This is untested...

Rob
-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx]
On Behalf Of Jonathan Mason
Sent: February 4, 2008 8:00 AM
To: rpg400-l@xxxxxxxxxxxx
Subject: Preparing dynamic SQL and parameter markers

Hi List

I'm trying to select a value from a flat file using embedded SQL and
because the filename is dynamic I believe I have to use a PREPARE
statement and provide a parameter marker for the variable I want to
select the value into.

My SQL statement is being built as:

C Eval wSQL = 'Select SUBSTR(CIFLD, 3, 8) '
+
C 'Into ? '
+
C 'From ' + %Trim(wFileName) + '
' +
C 'Where SUBSTR(CIFLD, 1,
2)=''CI'' ' +
C 'and SUBSTR(CIFLD,19,18)=' +
wQuote +
C MobileNo + wQuote

However when I run the PREPARE statement:

C/Exec SQL
C+ Prepare MySql from :wSQL
C/End-Exec

I am getting an error returned that says:

Message ID . . . . . . : SQL0104 Severity . . . . . . . : 30
Message type . . . . . : Diagnostic
Date sent . . . . . . : 04/02/08 Time sent . . . . . . :
12:07:31

Message . . . . : Token ? was not valid. Valid tokens: : <IDENTIFIER>.
Cause . . . . . : A syntax error was detected at token ?. Token ? is
not a
valid token. A partial list of valid tokens is : <IDENTIFIER>. This
list
assumes that the statement is correct up to the token. The error may
be
earlier in the statement, but the syntax of the statement appears to
be
valid up to this point.
Recovery . . . : Do one or more of the following and try the request
again:
-- Verify the SQL statement in the area of the token ?. Correct the
statement. The error could be a missing comma or quotation mark, it
could
be a misspelled word, or it could be related to the order of clauses.
-- If the error token is <END-OF-STATEMENT>, correct the SQL
statement
because it does not end with a valid clause.

Bottom

Am I wrong in thinking that this can be done? I came across an example
in the archives that looked like it was possible. I was hoping to avoid
having to use a cursor because there should only ever be one record
returned.

Thanks

Jonathan


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