Fuzzy Querying Capability at Core of a RDBMS
This chapter is focused in incorporating the fuzzy capabilities to a relational database management system (RDBMS) of open source. The fuzzy capabilities include connectors, modifiers, comparators, quantifiers, and queries. The extensions consider a more flexible DDL and DML languages. The aim is to show the design and implementation details in the RDBMS PostgreSQL. For this, a fuzzy query processor and fuzzy access mechanism has been designed and implemented. The physical fuzzy relational operators have been also defined and implemented. The flow of a fuzzy query through the different modules (parser, planner, optimizer, and executor) has been shown. Some experimental results have been included to demonstrate the performance of the proposal solution. These results show that the extensions have not decreased the performance of the RDBMS.