A data type as used in a typical relational database might be the set of integers, the set of character strings, the set of dates, or the two boolean values "true" and "false", and so on. The corresponding type names for these types might be the strings "int", "char", "date", "boolean", etc. It is important to understand, though, that relational theory does not dictate what types are to be supported; indeed, nowadays provisions are expected to be available for "user-defined" types in addition to the "built-in" ones provided by the system.