comments
- id：int- seller：varchar- buyer:varchar-comment:varchar- time：int
+ addcomments()+ deletecommen()+ altercommen()
collection
- id：int- house：varchar- user:varchar
+ addcollection()+ deletecollecti()
users
- id：int- tel：varchar- name:varchar- upwd:varchar- pic：int
+ adduser()+ changepwd()
orders
- id：int-seller：varchar- buyer:varchar- house:varchar- status：int
+ addorder()+ deleteorder()
house
- id：int- price：varchar- address:varchar- time:varchar- demand：int
+ addhouse()+ deletehouse()+ alterhouse()
