An attribute’s domain is a (possibly infinite) set of atomic values such as, for example, the set of integer number values or the set of real number values. In our cadastral database example, the domain of the Surname attribute, for instance, is a string, so any surname is represented as a sequence of text characters, i.e. as a string. The availability of other domains depends on the DBMS, but usually integer (the whole numbers), real (all numbers), date, yes/no and a few more are included. When a relation is created, we need to indicate what type of tuples it will store.