应用TADOConnection、TADODataSet和TADOCommand组件

unit U_AdoQuery;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs, StdCtrls, DB, ADODB, Buttons, DBClient, ExtCtrls,SQLEdit, Grids,  DBGrids;type  TForm1 = class(TForm)    DataSource1: TDataSource;    QueryButton: TButton;    EditCommandText: TSpeedButton;    ADOQuery1: TADOQuery;    SQLText: TMemo;    Connection: TADOConnection;    DBGrid1: TDBGrid;    Label1: TLabel;    procedure QueryButtonClick(Sender: TObject);    procedure EditCommandTextClick(Sender: TObject);  private    { Private declarations }  public    { Public declarations }  end;var  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.QueryButtonClick(Sender: TObject);begin  AdoQuery1.Close;  AdoQuery1.SQL.Clear;  AdoQuery1.SQL.Add(SQLText.Text);  AdoQuery1.Open;end;procedure TForm1.EditCommandTextClick(Sender: TObject);var  Command: string;begin  Command := SQLText.Text;  if EditSQL(Command, Connection.GetTableNames, Connection.GetFieldNames) then      SQLText.Text := Command;end;end.unit U_AdoCommand;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs, StdCtrls, DB, ADODB, Grids, DBGrids;type  TF_AdoCommand = class(TForm)    ADOConnection1: TADOConnection;    ADOCommand1: TADOCommand;    DataSource1: TDataSource;    DBGrid1: TDBGrid;    ADODataSet1: TADODataSet;    ADOCommand2: TADOCommand;    ExcuteButton: TButton;    CancelButton: TButton;    DataSource2: TDataSource;    DBGrid2: TDBGrid;    CancelAllButton: TButton;    ADODataSet2: TADODataSet;    ExcuteAllButton: TButton;    ComboBox1: TComboBox;    Label1: TLabel;    procedure ExcuteButtonClick(Sender: TObject);    procedure CancelButtonClick(Sender: TObject);    procedure CancelAllButtonClick(Sender: TObject);    procedure ExcuteAllButtonClick(Sender: TObject);    procedure FormCreate(Sender: TObject);  private    { Private declarations }  public    { Public declarations }  end;var  F_AdoCommand: TF_AdoCommand;implementation{$R *.dfm}procedure TF_AdoCommand.ExcuteButtonClick(Sender: TObject);beginif Combobox1.ItemIndex =0 then//调用第一个ADO命令组件的Excute方法，并在DBGrid1中显示查询结果  with ADOCommand1 do  begin      CommandType := cmdText;      CommandText :='select *  from  country';      ADODataSet1.Recordset := Execute;  endelse//调用第二个ADO命令组件的Excute方法，并在DBGrid2中显示查询结果  with ADOCommand2 do begin    CommandType := cmdText;    CommandText :='select *  from  employee';    ADODataSet2.Recordset := Execute;  end;end;procedure TF_AdoCommand.CancelButtonClick(Sender: TObject);begin  if Combobox1.ItemIndex =0 then   begin     ADOCommand1.Cancel;     ADODataSet1.Recordset :=nil ;   end  else   begin     ADOCommand2.Cancel;     ADODataSet2.Recordset :=nil;   end;end;procedure TF_AdoCommand.CancelAllButtonClick(Sender: TObject);begin   ADOCommand1.Cancel;   ADOCommand2.Cancel;   ADODataSet1.Recordset :=nil;   ADODataSet2.Recordset :=nil;end;procedure TF_AdoCommand.ExcuteAllButtonClick(Sender: TObject);vari: Integer;begin  ADOCommand2.CommandText :='Update';  for i := 0 to (ADOConnection1.CommandCount-1)  do      begin         if i=0 then             begin               ADOConnection1.Commands[i].CommandType := cmdText;               ADOConnection1.Commands[i].CommandText :='select *  from  country';                ADODataSet1.Recordset := ADOConnection1.Commands[i].Execute;             end         else  if i=1 then              begin               ADOConnection1.Commands[i].CommandType := cmdText;               ADOConnection1.Commands[i].CommandText :='select *  from  employee';               ADODataSet2.Recordset := ADOConnection1.Commands[i].Execute;             end;      end;end;procedure TF_AdoCommand.FormCreate(Sender: TObject);vari: Integer;begin  ComboBox1.Items.Clear;  //添加的列表项的数目等于ADOConnection1组件所相关的TADOCommand组件的个数  for i := 0 to (ADOConnection1.CommandCount-1)  do     //添加的列表项为相关TADOCommand组件的名称    Combobox1.Items.Add(ADOConnection1.Commands[i].Name) ;  Combobox1.ItemIndex :=0;end;end.