OleDbConnectionStringBuilder cb = new OleDbConnectionStringBuilder();
            cb.Provider = "LCPI.IBProvider.3.Free";
            cb.Add("Location", @"localhost:c:\data\myfdb.FDB");
            cb.Add("User ID", "sysdba");
            cb.Add("Password", "masterkey");
            cb.Add("ctype", "win1251");

OleDbConnection conn = new OleDbConnection(cb.ConnectionString);
            conn.Open();
            OleDbCommand cmd = conn.CreateCommand();
            cmd.Transaction = conn.BeginTransaction();
            cmd.CommandText = "select * from person";

OleDbDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);

                //читаю данные
                while (rdr.Read())
                {
                    string tmp = "";
                    for (int i = 0; i < rdr.FieldCount - 1; i++)
                    {
                        if (tmp != "") tmp += "\t";
                        tmp += rdr[i].ToString();
                    }

                    Console.WriteLine(tmp);
                }

                rdr.Close();

tmp += rdr[i].ToString();