unit main;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, DB, ZAbstractRODataset, ZAbstractDataset, ZDataset,
  ZConnection, Grids, DBGrids;

type
  TForm1 = class(TForm)
    ZConnection1: TZConnection;
    ZQuery1: TZQuery;
    btQuery: TButton;
    DataSource1: TDataSource;
    DBGrid1: TDBGrid;
    procedure btQueryClick(Sender: TObject);
    procedure FormActivate(Sender: TObject);
    procedure FormDeactivate(Sender: TObject);
  private
    { Private-Deklarationen }
  public
    { Public-Deklarationen }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.btQueryClick(Sender: TObject);
var
  n: integer;
begin
  n := 4;
  ZQuery1.Close;
  ZQuery1.SQL.Text := 'SELECT * FROM Systeme WHERE SystemNr = ' + IntToStr(n);
  ZQuery1.Open;
end;

procedure TForm1.FormActivate(Sender: TObject);
begin
  ZConnection1.Connect;
end;

procedure TForm1.FormDeactivate(Sender: TObject);
begin
  ZConnection1.Disconnect;
end;

end.