main.pas

Delphi7数据库开发教程,包含该书21套实例

unit main;

interface

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

type
  TForm1 = class(TForm)
    cbbDBNames: TComboBox;
    Label1: TLabel;
    memSQL: TMemo;
    btnSubmit: TButton;
    DBGrid1: TDBGrid;
    DCOMConnection1: TDCOMConnection;
    ClientDataSet1: TClientDataSet;
    DataSource1: TDataSource;
    btnDisconnect: TButton;
    Label2: TLabel;
    Label3: TLabel;
    edtUserName: TEdit;
    edtPassword: TEdit;
    procedure FormCreate(Sender: TObject);
    procedure btnDisconnectClick(Sender: TObject);
    procedure btnSubmitClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

//创建窗口时从服务器中获取服务器上数据库的别名，
//并添加到下拉列表框中
procedure TForm1.FormCreate(Sender: TObject);
var i:integer;
    DBNames:OleVariant;
begin
  with DCOMConnection1 do
  begin
    if not Connected then
       Connected := True;
    //从服务器获得数据库别名列表
    DBNames := AppServer.GetServerDBNames;
    //判断指定的variant变量是否是一个数组
    with cbbDBNames do
    begin
      if VarIsArray(DBNames) then
         for i := 0 to VarArrayHighBound(DBNames, 1) do
           cbbDBNames.Items.Add(DBNames[i]);
      //显示第一个选项
      if Items.Count > 0 then
         Text := Items[0];
    end;
  end;  
end;

关闭客户端数据集
procedure TForm1.btnDisconnectClick(Sender: TObject);
begin
  ClientDataSet1.Close ;
end;

//向应用服务器提交查询
procedure TForm1.btnSubmitClick(Sender: TObject);
begin
  //设置应用服务器的数据库别名
  if (cbbDBNames.Text = '') or (memSQL.Lines.Text = '') then exit;
  with ClientDataSet1 do
  begin
    Close;
    DCOMConnection1.AppServer.SetServerDBName(cbbDBNames.Text,
                              edtUserName.Text , edtPassword.Text );
    //执行此操作前请确保Provider的Options属性中包含了poAllowCommandText
    CommandText  := memSQL.Lines.Text;
    Open;
  end;
end;

end.