unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    DBGrid1: TDBGrid;
    ADOConnection1: TADOConnection;
    ADOQuery1: TADOQuery;
    Panel1: TPanel;
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    DataSource1: TDataSource;
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure FormShow(Sender: TObject);
  private
    { Private 宣言 }
  public
    { Public 宣言 }
  end;

var
  Form1: TForm1;

implementation

uses Unit2;

{$R *.dfm}

//=============================================================================
//  開始時の処理
//=============================================================================
procedure TForm1.FormShow(Sender: TObject);
begin
  Button2.Enabled := False;
  Button3.Enabled := False;
end;

//=============================================================================
//  フォームを閉じる時はDBも切断
//=============================================================================
procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  ADOConnection1.Connected := False;
end;

//=============================================================================
//  接続
//  テストなのでオブジェクト・インスペクタではなくコードで設定　
//=============================================================================
procedure TForm1.Button1Click(Sender: TObject);
var
  DataBase : String;
  UserID   : String;
  Password : String;
begin
    if Form2.ShowModal = mrOk then begin
      Update;
      if ADOConnection1.Connected then ADOConnection1.Connected := False;

      DataBase := Trim(Form2.LabeledEdit1.Text);
      UserID   := Trim(Form2.LabeledEdit2.Text);
      Password := Trim(Form2.LabeledEdit3.Text);

      ADOQuery1.Connection := ADOConnection1;
      DataSource1.DataSet  := ADOQuery1;
      DBGrid1.DataSource   := DataSource1;

      //ConnectionStringの設定
      ADOConnection1.Provider         := 'MSDAORA.1';
      ADOConnection1.ConnectionString := 'Data Source=' + DataBase +
                                         ';User ID='    + UserID   +
                                         ';Password='   + Password;

      //接続
      //なくてもクエリーを実行すれば接続する
      ADOConnection1.Connected := True;
    end;

  Button2.Enabled := ADOConnection1.Connected;
  Button3.Enabled := ADOConnection1.Connected;
end;

//=============================================================================
//  クエリー実行
//  テストなのでTADOConnectionの確認は行わない
//=============================================================================
procedure TForm1.Button2Click(Sender: TObject);
begin
  with ADOQuery1 do begin
    Close;
    SQL.Clear;
    SQL.Add('SELECT * FROM EMP');
    Open;
  end;
end;

//=============================================================================
//  切断
//=============================================================================
procedure TForm1.Button3Click(Sender: TObject);
begin
  ADOConnection1.Connected := False;

  Button2.Enabled := ADOConnection1.Connected;
  Button3.Enabled := ADOConnection1.Connected;
end;

end.

unit Unit2;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls;

type
  TForm2 = class(TForm)
    LabeledEdit1 : TLabeledEdit;
    LabeledEdit2 : TLabeledEdit;
    LabeledEdit3 : TLabeledEdit;
    Button1: TButton;
    Button2: TButton;
    procedure FormShow(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
  private
    { Private 宣言 }
    IniFileName  : String;
  public
    { Public 宣言 }
    DataBase : String;
    UserID   : String;
    Password : String;
  end;

var
  Form2: TForm2;

implementation

uses IniFiles;

{$R *.dfm}

//=============================================================================
//  設定をIniファイルから読出し
//=============================================================================
procedure TForm2.FormShow(Sender: TObject);
var
    AIni : TInifile;
begin
    IniFileName := ExtractFilePath(ParamStr(0)) + 'Login.ini';
    AIni := TIniFile.Create(IniFileName);
    try
     if FileExists(IniFileName) then begin
       LabeledEdit1.Text := AIni.ReadString('DBInfo', 'DataBase', '');
       LabeledEdit2.Text := AIni.ReadString('DBInfo', 'UserID',   '');
       LabeledEdit3.Text := AIni.ReadString('DBInfo', 'Password', '');
     end else begin
       LabeledEdit1.Text := 'ORACLEDB';
       LabeledEdit2.Text := 'SCOTT';
       LabeledEdit3.Text := 'TIGER';
     end;
    finally
      FreeAndNil(AIni);
    end;
end;
//=============================================================================
//  設定をIniファイルに保存
//=============================================================================
procedure TForm2.FormClose(Sender: TObject; var Action: TCloseAction);
var
    AIni : TInifile;
begin
  if ModalResult = mrOk then begin
    AIni := TIniFile.Create(IniFileName);
    try
      try
        AIni.WriteString('DBInfo','DataBase', LabeledEdit1.Text);
        AIni.WriteString('DBInfo','UserID',   LabeledEdit2.Text);
        AIni.WriteString('DbInfo','PassWord', LabeledEdit3.Text);
      except
      end;
    finally
      FreeAndNil(AIni);
    end;
  end;
end;

end.

//=============================================================================
//  接続
//  テストなのでオブジェクト・インスペクタではなくコードで設定　
//=============================================================================
procedure TForm1.Button1Click(Sender: TObject);
var
  DataBase : String;
  UserID   : String;
  Password : String;
begin
  Form2 := TForm2.Create(Self);
  try
    if Form2.ShowModal = mrOk then begin
      Update;
      if ADOConnection1.Connected then ADOConnection1.Connected := False;

      DataBase := Trim(Form2.LabeledEdit1.Text);
      UserID   := Trim(Form2.LabeledEdit2.Text);
      Password := Trim(Form2.LabeledEdit3.Text);

      ADOQuery1.Connection := ADOConnection1;
      DataSource1.DataSet  := ADOQuery1;
      DBGrid1.DataSource   := DataSource1;

      //ConnectionStringの設定
      ADOConnection1.Provider         := 'OraOLEDB.Oracle.1';
      ADOConnection1.ConnectionString := 'Data Source=' + DataBase +
                                         ';User ID='    + UserID   +
                                         ';Password='   + Password;
      //接続
      //なくてもクエリーを実行すれば接続する
      ADOConnection1.Connected := True;
    end;
  finally
    FreeAndNil(Form2);
  end;

  Button2.Enabled := ADOConnection1.Connected;
  Button3.Enabled := ADOConnection1.Connected;
end;