insert fails on tDbf table
lazarus / 16-Databases

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garydale · 2011-07-21 21:26

I'm using Lazarus 0.9.28.2-12 beta on a Debian/Wheezy AMD64 system.
I'm attempting to append records from one .dbf file to another (both
originally created using Visual dBASE 5.7).

Whether I have a .mdx file with them or not, when I attempt to insert
the first record in the empty database, I get an error:
Project Myproject raised exception class 'eDatabaseError' with
message:
###(gdb unparsed remainder:s 0xffffffffffec out of bounds>)###

The database did open correctly and I can display a list of its
fields. I've changed the Linux permissions on the database files to
A+RWX but that didn't help.

Using ShowMessage I have verified that it is the statement
"mydbf.insert;" that is throwing the exception.

Any ideas anyone?

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BigChimp · 2011-07-22 05:58

I'm not that knowledgeable about DBF - just wrote my first DBF program
myself, but:
Might be that you have an old FPC/Lazarus version with a bug that has
since been fixed. What is your version?Might be your code (though I
suspect not, based on your post). What exactly is the relevant
code?Could even be that support for that version of DBF files is
faulty. Does editing/updating records work? And selecting/reading
them?
If all else fails, you could try to write a simple test program with
sample data and put it on the bugtracker... that will at least make
sure the bug (if it is one) is tracked and dealt with by the devs.

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garydale · 2011-07-22 21:14

Got it. I tried running the Win32 version in a Virtual Machine and got
a better error message that pointed to a bad file path. When I fixed
that in Windows by removing the file path, it also fixed it in Linux.
I also tried Lazarus under Wine but can't get my application to run.

I'm not sure why the file opens and displays the fields when it has a
"bad" file path. It's not actually bad - just handled that way. I had
the full path to the file instead of a relative path from the
application directory.

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garydale · 2011-07-23 19:39

Spoke too soon. It's giving me the same error under Linux as before.
It runs fine under Win32 and under Wine however.

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garydale · 2011-07-30 16:24

OK, after making substantial changes to my program (but not to the
part hat's giving me the problem), I'm now getting a more descriptive
error message from the Linux executable. It's now telling me "Dataset
is read-only."

The code segment in question is:
 Code: [Select]             if postalcodetable.Locate('POSTALCODE',
CurPost, [loCaseInsensitive]) then begin
showMessage('editing ' +
postalcodetable.FieldByName('POSTALCODE').Text);
                 postalcodetable.Edit;
             end else begin
showMessage('inserting ' + CurPost);
                 postalcodetable.Insert;
showMessage('inserted ' + CurPost);
                 postalcodetable.FieldByName('POSTALCODE').AsString :=
CurPost;
             end;
The postalcodetable is of type TDbf and is opened with ReadOnly set to
False. The .dbf and .mdx files are both a+rw (everyone has read-write
privileges).

When the above code runs, I get the "inserting" message directly
before the database.Insert but not the "inserted" message immediately
after it. Instead I get the "read-only" error popup message reported
at the top.

Any ideas?

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felipemdc · 2011-07-30 20:15

Maybe attaching here the project would help if someone wants to take a
look

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garydale · 2011-07-31 00:09

The full source code is rather large. I've just refactored it to
isolate a couple of classes and hide the implementation of
persistence. It's still working under Windows/Wine but not under
Linux.

I notice that the Windows/Wine version is 9.30 while the Linux version
is 9.28.2.

Also, noted that I get the "Dataset is read-only" error when I launch
my application from Dolphin (the KDE file explorer) while running it
from Lazarus gives me the error I originally reported.

I'm wondering if the error is related to the difference in version
numbers? Unfortunately it looks like the Debian/Sid version of Lazarus
(which is 9.30) isn't working right now.

Anyway, here's the complete code for the unit that is failing:

Code: [Select]unit PostalCodes;

{$mode objfpc}{$H+}

interface

uses
    Db, Dbf, Dialogs, Ridings, Classes, SysUtils;
type
  tPostCode = String;
  tWard = Integer;

  TPostalCode = Class(TObject)
    private
      PostalCode: tPostCode;
      FederalRiding,
      ProvincialRiding: tRidingCode;
      MunicipalWard: tWard;
    public
      constructor Create(const pCode: tPostCode; const Fed, Prov:
tRidingCode; const mWard: tWard);
      procedure getPostalCode(var pCode: tPostCode);
      procedure getFederalRiding(var Fed: tRidingCode);
      procedure getProvincialRiding(var Prov: tRidingCode);
      procedure getMunicipalWard(var mWard: tWard);
      procedure getProvince(var Province: tRidingType);
      procedure setPostalCode(const pCode: tPostCode);
      procedure setFederalRiding(const Fed: tRidingCode);
      procedure setProvincialRiding(const Prov: tRidingCode);
      procedure setMunicipalWard(const mWard: tWard);
      procedure load();
      procedure save();
      procedure maintain();
   end;

implementation

const postalcodetablename = 'POSTAL.DBF';
      postalcodetablepath = '';
      postalcodefield     = 'POSTALCODE';
      federalridingfield  = 'FEDERAL';
      provincialridingfield = 'PROVINCIAL';
      municipalwardfield  = 'MUNICIPAL';

var  postalcodetable: TDbf;

Procedure OpenTable(var aTable: TDbf; const TablePath, TableName:
String);
   begin
        aTable.FilePath  := TablePath;
        aTable.TableName := TableName;
        aTable.Open;
   end;


procedure rebuild(var aTable: TDbf);
  begin
      ShowMessage('rebuilding index for ' + aTable.TableName);
      aTable.Exclusive := True;
      aTable.PackTable;
      aTable.RegenerateIndexes;
      aTable.Exclusive := False;
      ShowMessage('rebuilt index for ' + aTable.TableName);
  end;


{ TPostalCode }

constructor TPostalCode.Create(const pCode: tPostCode; const Fed,
Prov: tRidingCode; const mWard: tWard);
  begin
      PostalCode := pCode;
      FederalRiding := Fed;
      ProvincialRiding := Prov;
      MunicipalWard := mWard;
  end;

procedure TPostalCode.getPostalCode(var pCode: tPostCode);
  begin
       pCode := Self.PostalCode;
  end;

procedure TPostalCode.getFederalRiding(var Fed: tRidingCode);
  begin
       Fed := Self.FederalRiding;
  end;

procedure TPostalCode.getProvincialRiding(var Prov: tRidingCode);
  begin
       Prov := Self.ProvincialRiding;
  end;

procedure TPostalCode.getMunicipalWard(var mWard: tWard);
  begin
       mWard := Self.MunicipalWard;
  end;

Procedure TPostalCode.getProvince(var Province: tRidingType);
  var First: Char;
  begin
      First := Self.PostalCode[1];
      case First of
         'A': Province := 'NL';
         'B': Province := 'NS';
         'C': Province := 'PE';
         'E': Province := 'NB';
         'G', 'H', 'J':
              Province := 'QC';
         'K', 'L', 'M', 'N', 'P' :
              Province := 'ON';
         'R': Province := 'MB';
         'S': Province := 'SK';
         'T': Province := 'AL';
         'V': Province := 'BC';
         'X': Province := 'NT';
         'Y': Province := 'YT';
      end;
  end;

procedure TPostalCode.setPostalCode(const pCode: tPostCode);
  begin
       Self.PostalCode := pCode;
  end;

procedure TPostalCode.setFederalRiding(const Fed: tRidingCode);
  begin
       Self.FederalRiding := Fed;
  end;

procedure TPostalCode.setProvincialRiding(const Prov: tRidingCode);
  begin
       Self.ProvincialRiding := Prov;
  end;

procedure TPostalCode.setMunicipalWard(const mWard: tWard);
  begin
       Self.MunicipalWard := mWard;
  end;

procedure TPostalCode.load();
  begin
     if Length(Self.PostalCode) <> 0 then
        if postalcodetable.Locate(postalcodefield, Self.PostalCode,
[]) then begin
           Self.FederalRiding    :=
postalcodetable.FieldByName(federalridingfield).Text;
           Self.ProvincialRiding :=
postalcodetable.FieldByName(provincialridingfield).Text;
           Self.MunicipalWard    :=
postalcodetable.FieldByName(municipalwardfield).AsInteger;
        end else begin
           Self.FederalRiding    := '';
           Self.ProvincialRiding := '';
           Self.MunicipalWard    := 0;
        end
  end;

procedure TPostalCode.save();
  begin
       if postalcodetable.Locate(postalcodefield, Self.PostalCode, [])
then
          postalcodetable.Edit
       else begin
          postalcodetable.Insert;
          postalcodetable.FieldByName(postalcodefield).AsString :=
Self.PostalCode;
       end;
       postalcodetable.FieldByName(federalridingfield).AsString :=
Self.FederalRiding;
       postalcodetable.FieldByName(provincialridingfield).AsString :=
Self.ProvincialRiding;
       postalcodetable.FieldByName(municipalwardfield).AsInteger :=
Self.MunicipalWard;
       postalcodetable.Post;
  end;

procedure TPostalCode.maintain();
begin
   postalcodetable.Close;
   postalcodetable.Exclusive := True;
   OpenTable(postalcodetable, postalcodetablepath,
postalcodetablename);
   postalcodetable.AddIndex(postalcodefield, postalcodefield,
[ixPrimary, ixUnique]);
   postalcodetable.AddIndex(federalridingfield, federalridingfield,
[]);
   postalcodetable.AddIndex(provincialridingfield,
provincialridingfield, []);
   postalcodetable.AddIndex(municipalwardfield, municipalwardfield,
[]);
   rebuild(postalcodetable);
   postalcodetable.Close;
   postalcodetable.Exclusive := False;
   OpenTable(postalcodetable, postalcodetablepath,
postalcodetablename);
end;

initialization;
  postalcodetable := TDbf.Create(nil);
  postalcodetable.ReadOnly  := False;
  postalcodetable.Exclusive := False;
  OpenTable(postalcodetable, postalcodetablepath,
postalcodetablename);


finalization;
  postalcodetable.Close;

end.

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garydale · 2011-07-31 19:50

OK, I got 9.30 to install under Linux but the problem is still there.

Note: I can rebuild the indexes for the files even though the .mdx
files have the same security settings as the .dbf files. It's just
trying to edit or insert that seems to fail.