## Approximation in Databases (1995)

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### Other Repositories/Bibliography

Venue: | In PPCP'93, First International Workshop on Principles and Practice of Constraint Programming |

Citations: | 124 - 12 self |

### BibTeX

@INPROCEEDINGS{Libkin95approximationin,

author = {Leonid Libkin},

title = {Approximation in Databases},

booktitle = {In PPCP'93, First International Workshop on Principles and Practice of Constraint Programming},

year = {1995},

publisher = {Springer}

}

### Years of Citing Articles

### OpenURL

### Abstract

One source of partial information in databases is the need to combine information from several databases. Even if each database is complete for some "world", the combined databases will not be, and answers to queries against such combined databases can only be approximated. In this paper we describe various situations in which a precise answer cannot be obtained for a query asked against multiple databases. Based on an analysis of these situations, we propose a classification of constructs that can be used to model approximations. A major goal is to obtain universality properties for these models of approximations. Universality properties suggest syntax for languages with approximations based on the operations which are naturally associated with them. We prove universality properties for most of the approximation constructs. Then we use them to design languages built around datatypes given by the approximation constructs. A straightforward approach results in langauges that have a numb...