Re: Help with structs and .ec
I've not seen any response to this question, so I'm sending my response,
which consists of a number of other questions, as well as one or two
pertinent (I hope) observations.
>From: uunet!turq.b8.ingr.com!randy (Randy Paries)
>Subject: Help with structs and .ec
>Date: Thu, 5 Nov 92 12:26:57 CST
>X-Informix-List-Id: <list.1574>
> I am having problems fetching into a structure when using a prepare.
> $struct open{
> int var1;
> int var2;
> char var3;
> };
> $struct open open_rec;
> main()
> {
> $declare X cursor for
> select * from table where table.var1 = 2;> $open;
** Open what?
> $fetch X into $open_rec;
> }
> This above example works ok.
As in compiles OK? Or runs OK?
I don't think it should even compile, because the open statement clearly
suffers from a syntax error (no cursor name). I could easily believe that
the compiler would not then analyse the fetch statement. Also, you should be
very careful about using keywords as identifiers. OPEN is a keyword. Using
a structure type called "open" might confuse the ESQL/C preprocessor.
> The following example fails on the compile with the following error:
> line 13: RECORD objects 'open_rec' are not allowed in this list
> $struct open{
> int var1;
> int var2;
> char var3;
> };
> $struct open open_rec;
> main()
> {
> char qvar[200];
> strcpy(qvar,"select * from table where table.var1 = 2");
> $prepare Y from $qvar;
> $declare X cursor for Y;
> $open;
** Open what?
> $fetch X into $open_rec;
> }
> if I replace $fetch X into $open_rec; with
> $fetch X into $open_rec.var1,$open_rec.var2,$open_rec.var2
> it works ok.
As in compiles? Or runs?
> The problem is the tables that I need to fetch in real life have
> LOTS of columns.
So you have five choices (at least):
(0) Fix the syntax errors in the open statements:-)
(1) Redesign your tables so they have fewer columns.
(2) Produce a program which lists all the columns in a table so that
you can generate the elements of the record automatically.
(3) Use I4GL and the RECORD LIKE facility.
(4) Write your own preprocessor to provide you with the equivalent of
the I4GL record.* facility.
Yours,
Jonathan Leffler (johnl@obelix.informix.com) #include <disclaimer.h>