Delphi ADO访问数据库

unit ado;

interface

uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, ADODB, DB, Grids, DBGrids, StdCtrls;

type

  TfrmMain = class(TForm)

    edt1: TEdit;

    edt2: TEdit;

    edt3: TEdit;

    edt4: TEdit;

    btnTest: TButton;

    lbl1: TLabel;

    lbl2: TLabel;

    lbl3: TLabel;

    lbl4: TLabel;

    dbgrd: TDBGrid;

    dsDataSource: TDataSource;

    conADOConnection: TADOConnection;

    qryADOQuery: TADOQuery;

    dsADODataSet: TADODataSet;

    procedure OnFormCreate(Sender: TObject);

    procedure btnTestClick(Sender: TObject);

  private

    { Private declarations }

  public

    { Public declarations }

  end;

var

  frmMain: TfrmMain;

implementation

{$R *.dfm}

procedure TfrmMain.btnTestClick(Sender: TObject);

var i1,i2,i3,i4:Integer;

begin

  i1 :=0;

  i2 :=0;

  i3 :=0;

  i4 :=0;

  with qryADOQuery do

    begin

      Close;

      SQL.Text :='select FSalage from Person';

      Open;;

    end;

  while not qryADOQuery.Eof do

        begin

          case qryADOQuery.FieldByName('FSalage').AsInteger of

              0..999:Inc(i1);

              1000..1999:Inc(i2);

              2000..2999:inc(i3);

          else

            inc(i4);

          end;

          qryADOQuery.Next;

        end;

  edt1.Text := IntToStr(i1);

    edt2.Text := IntToStr(i2);

      edt3.Text := IntToStr(i3);

        edt4.Text := IntToStr(i4);

end;

procedure TfrmMain.OnFormCreate(Sender: TObject);

begin

conADOConnection.ConnectionString :='Provider=Microsoft.Jet.OLEDB.4.0;Data Source='+extractfilepath(Application.ExeName)+'Test.mdb;Persist Security Info=False';

dsADODataSet.Active := False;

dsADODataSet.Active := True;

end;

end.