update.pas

《delphi数据库设计与实例开发》随书光盘

unit Update;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DB, StdCtrls, Grids, DBGrids, DBTables;

type
  TForm1 = class(TForm)
    Query1: TQuery;
    DBGrid1: TDBGrid;
    GroupBox1: TGroupBox;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    Label5: TLabel;
    Label6: TLabel;
    Edit1: TEdit;
    Edit2: TEdit;
    Edit3: TEdit;
    Edit4: TEdit;
    Edit5: TEdit;
    Edit6: TEdit;
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    DataSource1: TDataSource;
    Query2: TQuery;
    procedure Query1AfterOpen(DataSet: TDataSet);
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure Button3Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  Choose:String;


implementation

{$R *.dfm}


procedure TForm1.Query1AfterOpen(DataSet: TDataSet);
begin
  edit1.Text:=Query1.FieldByName('EmpNo').AsString;
  edit2.Text:=Query1.FieldByName('LastName').AsString;
  edit3.Text:=Query1.FieldByName('FirstName').AsString;
  edit4.Text:=Query1.FieldByName('PhoneExt').AsString;
  edit5.Text:=DateTimeToStr(Query1.FieldByName('HireDate').AsDateTime);
  edit6.Text:=FloatToStr(Query1.FieldByName('Salary').AsFloat);
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
 edit1.Enabled:=True;
 edit2.Enabled:=True;
 edit3.Enabled:=True;
 edit4.Enabled:=True;
 edit5.Enabled:=True;
 edit6.Enabled:=True;
 Button2.Enabled:=True;
 Button3.Enabled:=True;
 Button1.Enabled:=False;
 Choose:='Update';
end;

procedure TForm1.Button2Click(Sender: TObject);
var
Location:String;
begin
 if (Choose='Update') then
  begin
  Location:=edit1.Text;
  with Query2 do
  begin
   SQL.Clear;
   SQL.Add('update employee');
   SQL.Add('set EmpNo='''+edit1.Text+'''');
   SQL.Add(',LastName='''+edit2.Text+'''');
   SQL.Add(',FirstName='''+edit3.Text+'''');
   SQL.Add(',PhoneExt='''+edit4.Text+'''');
   SQL.Add(',HireDate=:HD');
   SQL.Add(',Salary=:SY  ');
   SQL.Add('Where EmpNo='+''''+Query1.FieldByName('EmpNo').AsString+'''');
   ParamByName('HD').AsDateTime:=StrToDateTime(edit5.Text);
   ParamByName('SY').AsFloat:=StrToFloat(edit6.Text);
   ExecSQL;
  end;
  Query1.Close;
  Query1.Open;
  Query1.Locate('EmpNo',Location,[loPartialKey]);
  edit1.Enabled:=False;
  edit2.Enabled:=False;
  edit3.Enabled:=False;
  edit4.Enabled:=False;
  edit5.Enabled:=False;
  edit6.Enabled:=False;
  Button2.Enabled:=False;
  Button3.Enabled:=False;
  Button1.Enabled:=True;
  MessageBox(Application.Handle,'修改成功','提醒',MB_OK OR MB_ICONINFORMATION);
  end;

end;

procedure TForm1.FormCreate(Sender: TObject);
begin
 Query1.DatabaseName:='DBDEMOS';
 Query2.DatabaseName:='DBDEMOS';
 with Query1 do
  begin
   SQL.Clear;
   SQL.Add('Select * from employee');
   Close;
   Open;
  end;
end;

procedure TForm1.Button3Click(Sender: TObject);
var
 i:integer;
begin
 i:=MessageBox(Application.Handle,'您确定要取消此次操作吗?','提醒',MB_YESNO OR MB_ICONWARNING);
 if i=6 then
 begin
  Query1AfterOpen(Query1);
  edit1.Enabled:=False;
  edit2.Enabled:=False;
  edit3.Enabled:=False;
  edit4.Enabled:=False;
  edit5.Enabled:=False;
  edit6.Enabled:=False;
  Button2.Enabled:=False;
  Button3.Enabled:=False;
  Button1.Enabled:=True;
 end;

end;

end.