iterator erase(iterator pos)
Erase element at position pos.
The valid position in the container's range to erase.
The next position after the erased element.
iterator erase(iterator first, iterator last)
Erase elements in range [first, last).
The open boundary of the range.
The closed boundary of the range.
The next position after the erased elements.
The iterator pos in the functions must be a read-write iterator, can't be read only.
http://www.cplusplus.com/reference/stl/vector/erase.html
db_vector