SQLite:Unexpected Column Not Found After Upgrading To Lazarus 3.4
lazarus / 16-Databases

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Wilko500 · 2024-07-03 16:18

Background
I have a working program to migrate MS Access database data to SQLite
that has been ok for many months.  A change was required to the SQLite
data structure so I re-ran the "working" program but had problems with
the following line but only on the second call to the function.
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   iRes:=
dbQuery.FieldByName(strKey).AsString;  //This failing for ColUnits The
SQL for the query was correct, copied from ShowMessage and run in the
database browser, producing the expected output.  After several hours
of frustrated head scratching I hard coded a fix to jump over this
troublesome piece of code.

Next I started getting Operation cannot be performed on active
dataset. Searching the forum I found this from BigChimp, 2012

Quote    QDetail.Close;
      QDetail.SQL.Text:=Format(AdresLatest, [inttostr(NameID)]);
      QDetail.Open;
and this from Knipfty on the same post

QuoteI've found that anytime you change the SQL Text property, the
dataset needs to be closed.  The IDE does this automatically and
forces you to set active to true to see the result.  It doesn't
surprise me that you need to do this programically as well.

Putting .close in before each of my SQL.Text statements fixed all my
problems.  It seems to me that there has been some kind of change
within the IDE and possible the version of FPC I was using (maybe Laz-
FPC 3.3.1-3.9.9 not certain of the version) and the Laz-FPC 3.4-3.2.2
I use currently.

Are internal changes such as these documented and if so where?

Huge thanks to both BigChimp and Knipfty

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H₂SO₄ · 2024-07-04 04:49

Quote from: Wilko500 on July 03, 2024, 06:18:31 pmAre internal changes
such as these documented and if so where?

You can always look through the commit history of the compiler source
tree on GitLab; or more specifically, that of the  fcl-db  package
which contains the database units.

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af0815 · 2024-07-04 06:38

Quote from: Wilko500 on July 03, 2024, 06:18:31 pmPutting .close in
before each of my SQL.Text statements fixed all my problems. 
To close the Query before i change a statement (or add) was normal for
ages for me (exactly since my Delphi 7 times). Maybe it was accepted
by accident sometimes, so it was no internal change - more a bugfix
:-)