Firebird: How to get updated a updated files list after a drop table
commit
lazarus / 16-Databases

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MoellerCLaus · 2014-12-26 19:25

On a form of mine I need to let the users have to possiblity to
"drop"/erase a table.

The table is dropped - gone. But the read to
ZConnection1.GetTableNames('',Tabeller) does not seem to be
updated/actual.
Clearly I missed something! The connection is on autocommit.

Any hints highly appreciated.


Code: [Select]procedure TDatabaseSeeForm.DeleteTableExecute(Sender:
TObject);
begin
  If MessageDlg('Slet tabel ' + StringGrid1.Cells[0,StringGrid1.Row] +
'?',
    mtConfirmation,[mbYes,mbNo],0) <> MrYes Then Exit;
  With ZQuery1.SQL do
    Begin
      Clear;
      Add('Drop table ' + StringGrid1.Cells[0,StringGrid1.Row]);
    End;
  Try
    ZQuery1.ExecSQL;
  Except
    on E: EDatabaseError do
      begin
        MessageDlg('Error', 'A database error has occurred. Technical
error message: ' +
            E.Message, mtError, [mbOK], 0);
      end;
  end;
  IndlaesDatabasen;
end;


procedure TDatabaseSeeForm.IndlaesDatabasen;
Var A : Integer;
begin
  // Check if tables are there
  Tabeller := TStringList.Create;
  MainForm.ZConnection1.GetTableNames('',Tabeller);
  A := 0;
  StringGrid1.RowCount := 1;
  While A < Tabeller.Count Do
    Begin
      If Pos('$',Tabeller.Strings[A]) = 0 Then
        Begin
          StringGrid1.RowCount := StringGrid1.RowCount + 1;
          StringGrid1.Cells[0,StringGrid1.RowCount-1] :=
Tabeller.Strings[A];
        end;
      Inc(A);
    end;
end;

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patyi · 2014-12-26 20:50

For this task I use separate - secondary - connection component,
because have to close and reopen the connection to be refresh the
table list calling with GetTableNames() function.

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MoellerCLaus · 2014-12-27 07:35

Thanks - this might be a way through.
I had hoped for a "refresh" procedure or function.

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EgonHugeist · 2014-12-27 15:57

@MoellerCLaus

Note:

Zeos-internals are caching such informations. Which means Result of
GetTableNames is allways same as long you're connected.

You can flush the whole cache by using
TZConnection.DbcConnection.GetMetadata.ClearCache;

There is a feature request to get the caches flushed by object and/or
purpose:
http://sourceforge.net/p/zeoslib/tickets/104/

Or just follow suggestion of Patyi.

Michael