unit3.pas

应用ADO技术在Delphi中进行客户信息管理系统的开发。系统设计分为数据库设计和功能模块设计两部分。本系统的数据分为两部分：客户信息和系统用户信息。所以要设计两个表：Customers和Users

unit Unit3;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DB, ADODB, StdCtrls, Buttons;

type
  TFrmLogin = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    EdtUsrName: TEdit;
    EdtPass: TEdit;
    BtnOK: TBitBtn;
    BtnExit: TBitBtn;
    ADOQryUser: TADOQuery;
    DSUser: TDataSource;
    procedure BtnExitClick(Sender: TObject);
    procedure BtnOKClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  FrmLogin: TFrmLogin;

implementation

uses Unit1;

{$R *.dfm}

procedure TFrmLogin.BtnOKClick(Sender: TObject);
var
  CmdStr:string;
  UsrType:integer;
begin
  ADOQryUser.SQL.Clear;
  CmdStr:='select * from Users where 用户名='+QuotedStr(EdtUsrName.Text)
  +'and 口令='+QuotedStr(EdtPass.Text);
  ADOQryUser.SQL.Add(CmdStr);
  ADOQryUser.Open;
  if ADOQryUser.RecordCount<>0 then
  begin
    UsrType:=ADOQryUser.FieldList[2].AsInteger;
    FrmMain.Login.enabled:=false;
    FrmMain.Logout.enabled:=true;
    if UsrType=0 then
    begin
      FrmMain.Support.enabled:=true;
      FrmMain.Query.enabled:=true;
    end
    else
    begin
      FrmMain.Support.enabled:=false;
      FrmMain.Query.enabled:=true;
    end
  end
  else
    if(messagedlg('输入的用户名与口令不对！是否要重输？',mtinformation,
    [mbyes,mbno],0)<>mryes) then
    close;
end;

procedure TFrmLogin.BtnExitClick(Sender: TObject);
begin
  close;
end;

end.