ZDataset.Locate + loPartialKey
lazarus / 16-Databases

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tintinux · 2024-12-02 15:47

Hi

With Zeos 8.0, I found that the TZQuery.Locate method with
loPartialKey doesn't work anymore as usual.
At least using Ubuntu 24.04, Lazarus 3.6, and MariaDb Ver 15.1 Distrib
10.11.8-MariaDB, for debian-linux-gnu (x86_64)

Unfortunately, I can't post on the ZeosLib forum (blocked, unable to
access sourceforge.io) and don't find a related post elsewhere.
But I don't know if the issue is related to ZeosLib or Lazarus...

Problem is :
When the first characters of an existing key are entered, the result
of Locate returns false (and the position in the Dataset don't
change).
When a full existing key is entered, the Locate returns true and
position is changed, as expected.
Looks like [loPartialKey] is ignored.

I'm sure that it was ok with Zeos 7 and the same code and
configuration.

I can easily reproduce with this code example (only one string field).

Code: [Select]procedure TForm1.Edit1Change(Sender: TObject);
begin
  if ZreadonlyQuery1.Locate ('Account', edit1.Text, [loPartialKey] )
then
    caption := 'found'
  else
    caption := 'not found';
end;  
I have attached the full Lazarus project.
Enter the name, username and password of your database in
Zconnection1, and
Code: [Select]CREATE TABLE Accounts ( Account VARCHAR(10) NOT NULL );
INSERT INTO Accounts VALUES ('1000'), ('1005'), ('2000');
Or you can adapt the code to an existing table...

Any ideas or workaround ?

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tintinux · 2024-12-03 14:19

The problem seems new with ZeosLib 8.0

I have installed ZeosLib 7.2.6 and it works fine as expected with the
example.
Some manual changes are required in the .lfm, I find no way to make it
compatible with both versions.

Unfortunately there are other bugs in this version, solved only by the
8.0.

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Sieben · 2024-12-03 22:30

Why not use SQLdb then?

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tintinux · 2024-12-04 08:14

You are off topic, but the answers to your question are :
1) SqlDb can attach to only one Database type (and sometimes to only
one Database version) at a time.
2) SqlDb doesn't exist for Delphi AFAIK, and many developers are
required to use it and don't want to have to master too many packages
3) I would have all my projects to change and test, with no known
advantage.
4) I am sure that a workaround or a fix will be find to solve my small
issue
Regards

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silvercoder70 · 2024-12-10 09:49

I typically use Filter/Filtered properties of the query with LIKE

Not sure how well that would work in your scenario?

if Edit1.Text = '' then Query1.Filtered := False else begin
Query1.Filter := ...; Query1.Filtered := True;
end;

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tintinux · 2024-12-17 10:51

Hi

The bug is fixed in the SVN of ZeosLib.

More details here.

Cheers