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before this approach to database updates becomes practically useful. Several
extensions to DLP are possible. It is relatively simple to extend DLP to handle
delete queries with universally quantified variables. An extension of DLP that
allows hypothetical reasoning is described in Manchanda [1987a].
Acknowledgments
We wish to thank the referees for their useful comments. We have benefited
from discussions with Michael Kifer and Michael Gelfond.
References
1.
Abiteboul, S. and Granne, G. [1985] Update Semantics for Incomplete Databases,
Proceedings ofVLDB 85, Stockholm, 1-12.
2.
Abiteboul, S. and Vianu, V. [1987] A Transactio ...