Explain the term- Periodic recomputation
Periodic recomputation: Base values are often updated in bunches. Sometimes, it is possible to just recompute all derived attributes periodically without recomputing derived attributes after each base value is altered. Recomputation of all the derived attributes can be more proficient than incremental update since some derived attributes may depend on many base attributes and might be updated more than one time by an incremental approach.
Also, periodic recomputation is easier than explicit updates and less prone to bugs. While, if data set changes incrementally, some objects at a time, periodic recomputation is not practical since too many derived attributes may be recomputed when only a little are affected.