标准表达式中数据类型不匹配(Access)

public int AddDirectory(string sName,int nParentID)
      {
        //创建链接
        OleDbConnection conn = new OleDbConnection(ConfigurationManager.ConnectionStrings["zjjzxConn"].ConnectionString);

            ///定义SQL语句
                  System.DateTime datetime = Convert.ToDateTime(System.DateTime.Now.ToString());
        string cmdText = "INSERT INTO Directory(Name,ParentID,Contain,DirCount,FileCount,Flag,CreateDate)VALUES("
            + "'" + sName + "',"
             + "'" + nParentID + "',"
            + "'0'" + ","
            + "'0'" + ","
            + "'0'" + ","
            + "'1'" + ","
            +"'"+datetime+"'"
            + ")";



            ///创建Command
            OleDbCommand myCommand = new OleDbCommand(cmdText,conn);

///定义返回值
int nResult = -1;

            try
            {
                  ///打开链接
                  conn.Open();
                  ///执行SQL语句
                  nResult = myCommand.ExecuteNonQuery();
                  ///修改目录的数量
                  cmdText = "UPDATE Directory SET DirCount = DirCount + 1 WHERE DirID='" + nParentID.ToString() + "'";
                  myCommand.CommandText = cmdText;
                  nResult = myCommand.ExecuteNonQuery();
            }
            catch(OleDbException ex)
            {
                  ///抛出异常
                  throw new Exception(ex.Message,ex);
            }
            finally
            {   ///关闭链接
                  conn.Close();
            }
            ///返回nResult
            return nResult;
      }

我想，以后还是用sql server2000，因为access经常会出现一些摸名的错误！！
我的笨办法，另外建立一个表，表中的字段一个一个添加，sql中参数一个一个的测试，最后找到两个问题
1、数据库中的flag字段有问题，应该把是/否中style yes/no 改成
      true/false
2、下面的nParentID参数出错
cmdText = "UPDATE Directory SET DirCount = DirCount + 1 WHERE DirID='" + nParentID.ToString() + "'";
应改成
cmdText = "UPDATE Directory SET DirCount = DirCount + 1 WHERE DirID=" + nParentID.ToString() ;
3、说明：字段类型Name 文本,ParentID 数字, Flag是/否（true/false）,CreateDate 日期
小结，通过这次练习，终于完成了access中使用带参数的sql用法，希望给
和我一样的朋友带去快乐编程！！！