Raised exception class $C0000005 with message 'access violation'

[gustavototta]

Hello, how are you?

In my application there is a function to refresh the queries, but sometimes it is returning ACESS VIOLATION in the "OPEN" method. After clicking on "break" the pointer takes the code to the unit "ZDbcCache.pas", more precisely in the procedure TZRowAccessor.SetNull(ColumnIndex: Integer);

Could someone tell me how to solve this problem, please?

I currently use Delphi 10 Seattle with Zeos 8.0.0-beta

Previously with Delphi 7 and Zeos 7.2 the error was not displayed in the same application (I am in the process of migrating from D7 to Delphi Seattle)

Thank you all for your help!

Code: Select all

procedure RefreshQuery(vmo_ParQuery: TZQuery);
begin
   with (vmo_ParQuery as TZQuery) do
   begin
      DisableControls;
      Close;
      Open;
      EnableControls;
   end;
end;

____________


---------------------------
Debugger Exception Notification
---------------------------
Project Prisma5_MD.exe raised exception class $C0000005 with message 'access violation at 0x0075117a: read of address 0xc2b64469'.

[marsupilami]

Hello,

which database do you use? Could you try to create a small sample application that reproduces the problem? This really can help in tracking the bug down.

Best regards,

Jan

[gustavototta]

Hello,

Database: PostgreSql 9.3
I don't know if I can replicate the error in an isolated application, because our application has many routines to reach the problem. (we also have many external units)

We can think of something you can help us with, maybe a connection with anydesk or something similar.

What you think about?

Thanks!

[marsupilami]

I had a small discussion with the developer who did that part of Zeos. He will take a look today. We hope to be able to give you a more detailed answer tomorrow.

[gustavototta]

Hello how are you?

I understand perfectly, I'm waiting. Thanks in advance for your attention!

Hugs

[gustavototta]

I had a small discussion with the developer who did that part of Zeos. He will take a look today. We hope to be able to give you a more detailed answer tomorrow.

How are you?

Did you get any response from the ZeosLib developer regarding the access violation we mentioned, please?

Thanks

[marsupilami]

Hello,

yes, I got a response. He tried to reproduce the problem bud couldn't do so. He asked the question wether you use persistent fields, meaning Fields that are created in the Delphi IDE and where you can set properties during design time?

Unfortunately we are tight on time currently - so finding a time where we can access your computer and resolve the problem there is very limited.

Regarding the creation of a minimum working example:
Is there a query where you always get that error? What happens if you copy that form into a new project and try to open that query? What happens if you try to read data in this modified query from an empty table?

Best regards,

Jan

[gustavototta]

Hello how are you?

We managed to identify a field that was like fkCalculated, that was the problem.

This probably happened when migrating from Delphi 7 to Delphi 10 Seattle, in the past there was no problem and after updating with the new Delphi + Zeos 8.0 it started giving access violation.

Thank you for your attention!