On simplification of the context-null concept and its practical application
Hoang-Nam Bui, Dilip B. Kotak, Haruki Tamoto · 2003
The notion of context dependent null-values is an approach that exploits the relationship between a null-value and other known values in relational databases to deduce missing information. In a series of previous papers (1999, 2000, 2001) the context of a null-value was assumed to be defined by every known value associated with it in the database. In this paper, we suggest that only those known values that influence the null-value need to be considered. Using an example, we demonstrate that this simplified approach is more practical and easier to implement. We also show that, in order to deduce the missing information, the database designer would need to define how the known values influence it.