Delphi ADOQuery Demo

编辑器加载中..

procedure TForm2.FormCreate(Sender: TObject);
const
{ Connection string }
  ConnString =
'Provider=SQLOLEDB.1;Persist Security Info=False;' +
'User  +
'Auto Translate=True;Packet Size=4096;Use Encryption for Data=False;'+
'Tag with column collation when possible=False';
{ SQL Query }
  SQLStr = 'SELECT * FROM customer WHERE customer_id = :AnId;';
{ User access }
  UserName = 'db_user_name';
  PassWord = 'db_pass_word';
  Server = 'my.db.server';
var
  ADOConn  : TADOConnection;
  ADOQuery : TADOQuery;
  DataSrc  : TDataSource;
  Param    : TParameter;
begin
{ Create an ADO connection. }
  ADOConn := TADOConnection.Create(Self);
{ Set up the provider engine }
{ Set up the connection string. }
  ADOConn.ConnectionString := Format(ConnString,
    [UserName, PassWord, Server]);
{ Disable login prompt. }
  ADOConn.LoginPrompt := False;
try
    ADOConn.Connected := True;
except
    on e: EADOError do
begin
      MessageDlg('Error while connecting', mtError,
                  [mbOK], 0);
      Exit;
end;
end;
{ Create the query. }
  ADOQuery := TADOQuery.Create(Self);
  ADOQuery.Connection := ADOConn;
  ADOQuery.SQL.Add(SQLStr);
{ Update the parameter that was parsed from the SQL query: AnId. }
  Param := ADOQuery.Parameters.ParamByName('AnId');
  Param.DataType := ftInteger;
  Param.Value := 1;
{ Set the query to Prepared--it will improve performance. }
  ADOQuery.Prepared := true;
try
    ADOQuery.Active := True;
except
    on e: EADOError do
begin
      MessageDlg('Error while doing query', mtError,
                  [mbOK], 0);
      Exit;
end;
end;
{ Create the data source. }
  DataSrc := TDataSource.Create(Self);
  DataSrc.DataSet := ADOQuery;
  DataSrc.Enabled := true;
{ Finally, initialize the grid. }
  DBGrid1.DataSource := DataSrc;
end;

很简单的Demo。。。。有几个亮点，以便学习，第一次 首页 说明Delphi，没有消亡。。。