All officers elected and appointed under this chapter shall each, before entering upon the duties of their office, and within one week from the date of their election or appointment, give the bond required for any officers of this state, and shall make oath that they will truly, faithfully and impartially to the best of their ability, discharge the duties of their respective offices so long as they continue therein. Said oath may be taken before any person authorized to administer oaths or before the mayor of said city.