usertable
u_id <pk>poweruserNamepassWord
all_activity
a_id <pk>activity_nameactivity_organizerplace <fk>activity_begin_timeactivity_over_timeflagethemeu_id <fk>over
class_room
id <pk>Building_NumberRoom_NumberPeople_Numberflag
avtivity_user
id <pk>a_id <fk>u_id <fk>
