Lazarus and Access-Database
lazarus / 63-Database

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schand99 · 2020-11-19 12:52

Hi,

I have encountered a strange behaviour on Lazarus and MS Access
database:
I open a SQL Query which selects a number of records. On the open
records I have to check each record for the content of a field. I do
this within a repeat ... until loop:

A error raises up when rSSQL.Next points to the last record into
rSSQL, just befor rSSQL.EOF is true
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
...rSSQL.open;if not rSSQL.EOF do begin   rSSQL.First;   repeat      
... do something       rSSQL.Next;   until rSSQL.EOF;end; 
If in the same code I first point to the last records and after that I
point to the first record, there is no error
Is there anybody else having this problem? Or maybe someone who can
explain this strange behavior?
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
...rSSQL.open;if not rSSQL.EOF do begin   rSSQL.Last;           //  <-
this one   rSSQL.First;   repeat        ... do something     
 rSSQL.Next;   until rSSQL.EOF;end;

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Zvoni · 2020-11-20 08:26

I remember having similiar issues with DAO/ADO on VB6, that i had to
move to the last record, and then back to the first, because the EOF
and/or recordcount wasn't set properly or something like that.

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wp · 2020-11-20 09:59

The attached demo does the same: it iterates through an Access-based
dataset and counts the empty fields, and the error does not occur.

What is different to your case? I could imagine that the fact that the
query is attached to a DBGrid in my demo could cause .Last already
being called. So, please give more details, or better: upload a simple
compilable demo (only pas, lfm, lpi, lpr and database files, all in a
common zip, like I did).

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Zvoni · 2020-11-20 10:05

Found something:
http://allenbrowne.com/ser-29.html
Look at Point 5. Sounds like your Problem