Nonapplicable Nulls.

Nadine Lerat Witold Lipski Jr.

Published in: Theor. Comput. Sci. (1986)

Keyphrases

data exchange
relational algebra
inclusion dependencies
query answering
null values
databases
relational databases
schema mappings
information retrieval
search engine
preprocessing
data management
data integration
functional dependencies
incomplete information
relational model