tree

倒树:  必须是  ‘子’= prior ‘父’(本身start with 的该条记录关键字段,也就是start with Offspring = 'EVE'这条记录的offspring ( prior offspring )  )
  
  select b.*, level
    from BREEDING b
   start with Offspring = 'EVE'
  connect by prior offspring = Cow
 
正树:  必须是  ‘父’= prior ‘子’  (本身start with 的该条记录关键字段,也就是  start with Offspring = 'DELLA'这条记录的cow (prior Cow) )
    select b.*, level
    from BREEDING b
   start with Offspring = 'DELLA'
  connect by prior Cow = offspring