Normal form relation schemes a new characterization /
A new characterization of relational database schemes in normal forms is given. This characterization is based on the properties of the semilattice of closed sets of attributes. For the problems testing third and Boyce-Codd normal forma, which are known to be ^//'-complete for relation schemes,...
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| Main Authors: | |
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| Format: | Article |
| Published: |
1992
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| Series: | Acta cybernetica
10 No. 3 |
| Kulcsszavak: | Számítástechnika, Kibernetika |
| Subjects: | |
| Online Access: | http://acta.bibl.u-szeged.hu/12502 |
| Summary: | A new characterization of relational database schemes in normal forms is given. This characterization is based on the properties of the semilattice of closed sets of attributes. For the problems testing third and Boyce-Codd normal forma, which are known to be ^//'-complete for relation schemes, this new characterization helps establish polynomial algorithms if the input is a relation (matrix) rather than a relation scheme. The problem of approximation of an arbitrary family of functional dependencies by one in a normal form is also addressed. |
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| Physical Description: | 141-153 |
| ISSN: | 0324-721X |