The Research Of Fuzzy Query In Database Based On Computing With Words

The traditional relational database employs the relational model as its data organization, while the relational model is based on Boolean logic and accurate data tools, which cannot process ambiguous and uncertain information. The research on fuzzy query based on fuzzy logic therefore will bring database system into a new stage of development with vitality.Current main relational database systems could convert information between vagueness and precision realistically, non-destructively and accurately through some process methods and algorithms. This thesis primarily discuses that how fuzzy data can be converted into precise data on the database platform, which could help data query become fuzzified and could satisfy people’s need. Specifically, this thesis researches on the rational database fuzzy query technologies based on computing with words theory on the analysis of fuzzy sets theory and fuzzy query technology. Besides, it proposes solutions of single condition fuzzy query, complex conditions fuzzy query and weighted fuzzy query. The thesis also presents a Normal-distribution-like membership function model and anti-fuzzified calculation method. Through theoretical analysis, mathematical proof and experiment results, it concludes the advantages, disadvantages and application conditional of the new function model and classical model. Furthermore, the introduction of weight in fuzzy query scientifically reflects personal preference and tendency of users. Due to fuzzy of weight itself, the thesis proposes the concept of Interval Weights and a method to calculate interval weight. Finally, the thesis designs and implements a fuzzy query instance based on.NET platform, which demonstrates effectiveness and feasibility of the methods and algorithms proposed.Computing with words is one of the primary research aspects in intelligent information processing. It processes information based on sense and computes words rather than data, which imitates human brain’s thinking. There is not much research on fuzzy query technology based on CWW in domestic, and most mature database system has not support this function. However, this technology has broad prospect because it is closer to everyday life and more scientifically, reasonably and effectively when express some query conditions.