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Please use this identifier to cite or link to this item:
http://hdl.handle.net/2451/14613
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| Title: | FUNCTIONAL DEPENDENCIES AND INCOMPLETE INFORMATION |
| Authors: | Vassiliou, Yannis |
| Issue Date: | Oct-1980 |
| Publisher: | Stern School of Business, New York University |
| Series/Report no.: | IS-81-08 |
| Abstract: | Functional dependencies play an important role in relational database
design. They are defined in the context of a single relation which at
all times must contain tuples with non-null entries. In this paper we
examine an extension of the functional dependency interpretation to
handle null values, that is, entries in tuples that represent incomplete
information in a relational database. A complete axiomatization of
inference rules for extended functional dependencies is also presented.
Only after having such results is it possible to talk about
decompositions and normalization theory in a context of incomplete
information. Finally, we show that there are several practical
advantages in using nulls and a weaker notion of constraint satisfiability. |
| URI: | http://hdl.handle.net/2451/14613 |
| Appears in Collections: | IOMS: Information Systems Working Papers
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