this table has more than two rows,but i can only get two of them .if i can't get a column which can identify the location of it.I will have no way to know which row user selected.so the way which u said above is not valid.
my question is how to get the row in the table exactely.cause i want to update or delete the row which user selected,but if the row has no primary key I'll can't decided which row i can update or delete.