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Delphi & MS Access

Delphi & MS Access

Delphi & MS Access

I have some problems with saving a long text (longer then 255 characters) into MS Access database.

When I want to save it, the error screen pups up and it contains:

[0] General SQL error.
[Microsoft][ODBC Microsoft Access Driver] Invalid descriptor index
[Microsoft][ODBC Microsoft Access Driver] Invalid precision value

The data base is MS Access 2000: field ôtestö is defined as ômemoö. I am using Delphi 6, ODBC 5.2, TQuery:

Code for saving:

procedure TaOrganizacija.Button1Click(Sender: TObject);
  sql_niz: String;
  sql_niz:='INSERT INTO organizacije (test) VALUES (:test) ';
  Try QOrg.ExecSQL;
    On E: Exception Do
      ShowMessage('['+inttostr(E.HelpContext)+'] '+E.Message+#13#10);

The error occurs if I want to save in this field text, longer then 255 characters.

If I use QOrg.ParamByName('test').AsMemo:=mOpomba.Text; , the error screen pups up and it contains:

[0] General SQL error.
[Microsoft][ODBC Microsoft Access Driver] String data, right truncated (null).

If the text is shorter than there is no problem. If anyone already had similar problems, I would be thankful if you could share the solutions. Any kind of tips would be helpful.

RE: Delphi & MS Access

You will need to change the data type in the Access database from 'text' to 'memo'. Access limits the size of the 'text' data type to 255 characters.

RE: Delphi & MS Access

I allready have defined field test as memo in database.
Maybe another solution?

RE: Delphi & MS Access

This has always been a problem with MS Access as far as I know. You can store more then 255 characters into a memo field, but if you then try to handle it even in access, then you're out of luck. I know of no resolution, but I'd recommend going to one of the access newsgroups at news.microsoft.com

The MVP's in these forums are doing a fantastic job.

There is also a chance that your problem is described somewhere in Delphi newsgroups/forums

Good luck,


RE: Delphi & MS Access

I dont' understand the comment "if you then try to handle it even in access, then you're out of luck"
Access memo field cannot be indexed, but you  can certainly read and write them, filter on them etc.

RE: Delphi & MS Access

The limit on memo fields in Access is 64K.

1) What is QOrg.ParamByName('test').AsString declared as?
2) Is it a ShortString or a String/ANSIString?  From the little bit of Delphi that I do know, ShortStrings are limited to 255 chars - that might be where your problem is.
3) Has $LongStrings$ been turned off when building the program?

RE: Delphi & MS Access

Just a point about Access memo fields, from the help
The limit is
"65,535 when entering data through the user interface;
1 gigabyte when entering data programmatically."

But as XWB suggests I don't really think that is the problem.

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