学习 SQL 语句 - Insert、Update、Delete

unit Unit1;



interface



uses

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

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



type

  TForm1 = class(TForm)

    DBGrid1: TDBGrid;

    DataSource1: TDataSource;

    ADOConnection1: TADOConnection;

    ADODataSet1: TADODataSet;

    ADOCommand1: TADOCommand;

    Panel1: TPanel;

    Button1: TButton;

    Button2: TButton;

    Button3: TButton;

    Button4: TButton;

    procedure FormCreate(Sender: TObject);

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

    procedure Button3Click(Sender: TObject);

    procedure Button4Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



//添加

procedure TForm1.Button1Click(Sender: TObject);

begin

  try

    ADOCommand1.CommandText := 'INSERT INTO country VALUES("AAA", "BBB", "CCC", 111, 222)';

    ADOCommand1.Execute;



    ADOCommand1.CommandText :=

      'INSERT INTO country(Name,Capital,Continent) VALUES("XXX", "YYY", "ZZZ")';

    ADOCommand1.Execute;

  except on E: Exception do

    ShowMessage(E.Message);

  end;



  Button4.Click;

end;



//更新

procedure TForm1.Button2Click(Sender: TObject);

begin

  ADOCommand1.CommandText := 'UPDATE country SET Area=123,Population=456 WHERE Name="AAA"';

  ADOCommand1.Execute;



  ADOCommand1.CommandText := 'UPDATE country SET Capital="MMM" WHERE Capital="YYY"';

  ADOCommand1.Execute;



  Button4.Click;

end;



//删除

procedure TForm1.Button3Click(Sender: TObject);

begin

  ADOCommand1.CommandText := 'DELETE * From country WHERE Name="AAA"';

  ADOCommand1.Execute;

  ADOCommand1.CommandText := 'DELETE * From country WHERE Name="XXX"';

  ADOCommand1.Execute;



  Button4.Click;

end;



//查看

procedure TForm1.Button4Click(Sender: TObject);

begin

  with ADODataSet1 do begin

    Close;

    CommandText := 'SELECT * FROM country';

    Open;

  end;

end;



procedure TForm1.FormCreate(Sender: TObject);

var

  mdbFile: string;

begin

  {因要修改数据库, 特复制了一份}

  mdbFile := mdbFile + 'C:\Temp\dbdemos.mdb';



  ADOConnection1.ConnectionString :=

  'Provider=Microsoft.Jet.OLEDB.4.0;Data Source=' + mdbFile + ';Persist Security Info=False';



  ADOConnection1.LoginPrompt := False;

  ADOConnection1.Open; //ADOConnection1.Connected := True;



  ADODataSet1.Connection := ADOConnection1;

  ADOCommand1.Connection := ADOConnection1;



  DBGrid1.DataSource := DataSource1;

  DataSource1.DataSet := ADODataSet1;

end;



end.