Time and calendars play an important role in databases,
on the Semantic Web, as well as in mobile computing. Temporal data
and calendars require (specific) modeling and processing tools. CaTTS
is a type language for calendar definitions using which one can model
and process temporal and calendric data. CaTTS is based on a "theory
reasoning" approach for efficiency reasons. This article addresses type
checking temporal and calendric data and constraints. A thesis underlying
CaTTS is that types and type checking are as useful and desirable
with calendric data types as with other data types. Types enable
(meaningful) annotation of data. Type checking enhances efficiency and
consistency of programming and modeling languages like database and
Web query languages
