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DRKB - это самая большая и удобная в использовании база знаний по Дельфи в рунете, составленная Виталием Невзоровым

Создание DBExpress соединения в runtime

01.01.2007
{
  The normal way for Delphi and Kylix is just to check dbExpress,
  put a TSQLConnection on a form then double-click the TSQLConnection to display
  the Connection Editor and set parameter values (database path, connection name etc.)
  to indicate the settings.
 
  But in our example, all goes by runtime (path and login) with dbExpress we don't need
  an alias or the BDE either.
}
 
procedure TVCLScanner.PostUser(const Email, FirstName, LastName: WideString);
var
  Connection: TSQLConnection;
  DataSet: TSQLDataSet;
begin
  Connection := TSQLConnection.Create(nil);
  with Connection do
  begin
    ConnectionName := 'VCLScanner';
    DriverName := 'INTERBASE';
    LibraryName := 'dbexpint.dll';
    VendorLib := 'GDS32.DLL';
    GetDriverFunc := 'getSQLDriverINTERBASE';
    Params.Add('User_Name=SYSDBA');
    Params.Add('Password=masterkey');
    Params.Add('Database=milo2:D:\frank\webservices\umlbank.gdb');
    LoginPrompt := False;
    Open;
  end;
  DataSet := TSQLDataSet.Create(nil);
  with DataSet do
  begin
    SQLConnection := Connection;
    CommandText := Format('INSERT INTO kings VALUES("%s","%s","%s")',
      [Email, FirstN, LastN]);
    try
      ExecSQL;
    except
    end;
  end;
  Connection.Close;
  DataSet.Free;
  Connection.Free;
end;

Взято с сайта https://www.swissdelphicenter.ch/en/tipsindex.php