The need for supporting time varying information in databases has been recognized for quite some time. many authors have proposed numerous schemes to satisfy this need by incorporating one or two time attributes in the database unfortunately there has been confusion concerning the terminology and definition of these time attributes this paper proposes a new tazonomy of three times for use databases one that is more cleanly defined that my be conceptualized in a pictorial fashion and that defines several kinds of databases differentiated by their ability to represent temporal information the paper argues that future database management systems should support all three times to fully capture time varying behavior