数据库只保留某个用户10条浏览记录

public bool wbrowserinfo(int browsehid, string browsetitle, string browsepageurl, string browsetime, int userid)
        {
            sql = "select * from house_browselslist where userid=" + userid + "  order by house_browsetime desc";
            dt = DBUtility.DbHelperSQL.Query(sql).Tables[0];
            DataTable mydt = null;
            DataTable deldt = null;
            int hupdaet = 0;
            try
            {
                if (dt.Rows.Count >=10)
                {
                    int topid = dt.Rows.Count - 10;
                    sql = "select top " + topid + " * from house_browselslist where userid=" + userid + " order by house_browsetime asc";
                    deldt = DBUtility.DbHelperSQL.Query(sql).Tables[0];
                    if (deldt.Rows.Count > 0)
                    {
                        for (int i = 0; i < deldt.Rows.Count; i++)
                        {
                            hupdaet = DBUtility.DbHelperSQL.ExecuteSql("delete from house_browselslist where house_browselsid=" + Convert.ToInt32(deldt.Rows[i]["house_browselsid"].ToString()) + "");
                        }
                        sql = "select * from house_browselslist where userid=" + userid + " and house_browsehid=" + browsehid + " and house_browsepageurl='" + browsepageurl + "'  order by house_browsetime desc";
                        mydt = DBUtility.DbHelperSQL.Query(sql).Tables[0];
                        if (mydt.Rows.Count <= 0)
                        {
                            hupdaet = DBUtility.DbHelperSQL.ExecuteSql("insert into house_browselslist(house_browsehid,house_browsetitle,house_browsepageurl,house_browsetime,userid)values(" + browsehid + ",'" + browsetitle + "','" + browsepageurl + "','" + browsetime + "'," + userid + ")");
                        }
                    }
                }
                else
                {
                    sql = "select * from house_browselslist where userid=" + userid + " and house_browsehid=" + browsehid + " and house_browsepageurl='" + browsepageurl + "'  order by house_browsetime desc";
                    mydt = DBUtility.DbHelperSQL.Query(sql).Tables[0];
                    if (mydt.Rows.Count <= 0)
                    {
                        hupdaet = DBUtility.DbHelperSQL.ExecuteSql("insert into house_browselslist(house_browsehid,house_browsetitle,house_browsepageurl,house_browsetime,userid)values(" + browsehid + ",'" + browsetitle + "','" + browsepageurl + "','" + browsetime + "'," + userid + ")");
                    }
                }
                flag = true;
            }
            catch(Exception ex)
            {
                flag = false;
            }
            return flag;
        }