1.向上循环遍历
select c.*,level from dms_catalog c start with c.dms_ch_number='7' connect by prior c.dms_ch_parentid=c.dms_ch_numberand c.DMS_CH_NAME is not null;
２。向下循环遍历
selectc.*,level fromdms_catalog cstart withc.dms_ch_number='7'connect by prior c.dms_ch_number=c.dms_ch_parentid
说明：
表的自包含 树形结构
表结构中 字段 DMS_CH_PARENTID是外键 关联表主键DMS_CH_NUMBER
