Unable to use ESQLDatabaseError
lazarus / 16-Databases

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talorigomat · 2017-10-13 16:28

I'm trying to use ESQLDatabaseError to catch the error code and
message from a Firebird database but am having no joy.  I'm using the
following code:
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     try   
 dmMain.qrySite.ApplyUpdates();      dmMain.trnMain.Commit;    
except      on E:ESQLDatabaseError do      begin       
ShowMessageFmt('ErrorCode: %d; Message: %s', [E.ErrorCode,
E.Message]);      end;
if I use DatabaseError exception as

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     try   
 dmMain.qrySite.ApplyUpdates();      dmMain.trnMain.Commit;      on
E:EDatabaseError  do      begin        ShowMessage(E.Message);     
end;    end; 
Then I can catch the exceptions, however this form doesn't give me the
databases sql error code.

I'm using the SQLDB components to access the database and I'm using
Lazarus 1.8.0 RC4 with MS Windows 10.

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balazsszekely · 2017-10-14 05:16

What is the actual exception in your second code?

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talorigomat · 2017-10-17 13:59

Apologies.  Been away for a bit.  It is Violation of PRIMARY or UNIQUE
KEY constraint "UK_STENME" ON TABLE "SITE"

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rvk · 2017-10-17 14:06

Your second code is invalid because "on E: Exception" always needs to
be in an except-block.

Try this and tell us what classname you get.
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 try 
dmMain.qrySite.ApplyUpdates();  dmMain.trnMain.Commit;except  on E:
Exception do    Showmessage('Exceptionclass = ' + E.ClassName + ' / '
+ E.Message);end;
You can use the text of ClassName as the actual exceptionclass.
And if that class is really an SQLException you can use E.ErrorCode
after you change "on E: Exception" to "on E: Excptionclassname".

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talorigomat · 2017-10-17 15:40

Hi Rvk

thanks for pointing that out.  I accidentally deleted that before
posting.  Using the code you supplied the class name returned is
"EUpdateError".

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talorigomat · 2017-10-17 17:05

I've attached a simple project.  The place of interest is on the
btnSaveClick method on the Site form.  To illustrate I've included  on
E:ESQLDatabaseError, on E:EDatabaseError and on E: Exception in the
exception block.

Commenting out E:EDatabaseError and E: Exception blocks exceptions go
through to the default exception handler bypassing the
ESQLDatabaseError handler.  uncomment either E:EDatabaseError and E:
Exception then the exception is handled by the one that is
uncommented.  ESQLDatabaseError isn't catching anything.

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rvk · 2017-10-17 17:11

Quote from: talorigomat on October 17, 2017, 05:40:37 pmUsing the code
you supplied the class name returned is "EUpdateError".
So... don't use ESQLDatabaseError but use EUpdateError.

It also has a ErrorCode property.

ESQLDatabaseError isn't catching anything because that's not the
exception that occurs.

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talorigomat · 2017-10-19 16:32

Thanks for the helping with this rvk.  Now I understand this better.