The temporal feature integrated temporal attributes into Odysseus. These can be useful to predict unknown or future values of an attribute that develops over time. The temporal feature brings a complete semantics for temporal processing and is the foundation for spatio-temporal processing in Odysseus. The temporal feature is closely related to the moving object algebra by Güting et al.
Temporal attributes are attributes that not only have one value, but one value for each point in time for a certain time interval. In other words, a temporal attribute of a certain type is a function that for each point in time returns a value of its type. Take a temporal integer over the interval [0,5) as an example. It could be the function f(t) = 5 * t. Then, it has five values, one for each point in the time interval: 0→ 0, 1→ 5, 2→ 10, 3→ 15, 4→ 20.
Internally, for Odysseus, a temporal attribute looks just like a non-temporal attribute. For example, a temporal integer looks like an integer for Odysseus. Nevertheless, the temporal feature tricks Odysseus a little bit at this point. While the type in the schema stays an integer, the actual value is not an integer but a temporal integer. In the schema, a temporal attribute can be detected in the constraints, which is a key-value field each attribute has. Here, temporal is set to true.
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