There is created an administrative department of the city to be known as the department of finance. The department of finance shall be under the supervision of the director of finance. The director of finance shall be the chief financial officer of the city. In all cases where the fiscal affairs of the city are not expressly otherwise charged by the laws of the state to another department or officer, the director of finance shall have control and supervision over such fiscal affairs and shall act to promote, secure and preserve the financial interests of the city. (1957 code § 1.07.010.)