ASP.NET中SQL Server数据库访问通用类(2)

                command.CommandType = commandType;
                if (parameters != null)
                {
                    foreach (SqlParameter parameter in parameters)
                    {
                        command.Parameters.Add(parameter);
                    }
                }
                //实例化SqlDataAdapter
                SqlDataAdapter adapter = new SqlDataAdapter(command);
                //填充DataTable
                adapter.Fill(data);
            }
        }
        return data;
    }

2.连接式查询，利用SqlReader()返回DataReader对象实例
    /// <summary>
    /// 返回一个DataReader对象实例
    /// </summary>
    /// <param name="sql">要查询的SQL文本命令</param>
    /// <returns>DataReader对象实例</returns>
    public SqlDataReader ExecuteReader(string sql)
    {
        return ExecuteReader(sql, CommandType.Text, null);
    }

    /// <summary>
    /// 返回一个DataReader对象实例
    /// </summary>
    /// <param name="sql">要查询的SQL文本命令</param>
    /// <param name="commandType">要执行的查询语句的类型，存储过程或SQL文本命令</param>
    /// <returns>DataReader对象实例</returns>
    public SqlDataReader ExecuteReader(string sql, CommandType commandType)
    {
        return ExecuteReader(sql, commandType, null);
    }