Re: [libdbi-devel] dbi_result_next_row() in while() loop

[Eric B. <eb...@ya...>]

Christian,

I should've included some example code to help explain
what I was talking about.  However, I'm glad you where
able to understand what I was saying.

Error handling is great because it helps find sloppy
mistakes that the compiler will not find.  For
example,  I was able to find mistakes where someone
did a query like "SELECT x FROM y", then did a
dbi_result_get_long("x_nm").

My error handler does an assert() so that it forces
the developers to fix the problem rather than ignoring
it or not realizing that it occurred.

The problem with ignoring BAD_IDX is that it's the
same error code that occurs in a while loop and the
same error code that occurs in the example I just
gave.

Usually, we used a for loop, like this:

  rows = dbi_result_get_numrows(result);
  for (row = 0; row < rows; row++) {
    dbi_result_next_row(result);
    column = dbi_result_get_string(result, "A");
    printf("%s\n", column);
  }

However, we switched to using a while loop to use
fewer lines of code, like this:

  while (dbi_result_next_row(result)) {
    column = dbi_result_get_string(result, "A");
    printf("%s\n", column);
  }

The quick fix I came up with, to avoid rewriting the
while loops back to for loops, was to create a wrapper
function:

  int DbiResultNextRow(dbi_result Result)
  {
   dbi_result_t *result = Result;

   if ((result != NULL) && (result->currowidx <
       dbi_result_get_numrows(Result)))
   {
    return dbi_result_next_row(result);
   }
   else
   {
    return 0;
   }
  }

Thanks for your help.


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