Research On Fuzzy Aggregation Query Technology Based On Relational Databases

Almost existing databases are related databases. It is a waste of time and energy to change it into a fuzzy database. So to use these related databases is more practical and significant in fuzzy querying. Traditional related database only use and dispose precise data. Through using condition combination and expansion can’t realize to query fuzzy concepts of the nature language. In order to dispose fuzzy query conditions, we have to expand to the SQL. When using queries in some databases, users often face the question that need small result set, but have great record set. The raise of the query method have increased the capacity of query results too. This kind of method will reduced the database utilization rate and the users’use rata at the same time. Therefore, on the base of the fuzzy query using query method by aggregation function improve the questions that the fuzzy query efficiency isn’t high.This thesis researches the questions of fuzzy aggregation query on relational databases. First this thesis put forward the simple fuzzy aggregation query.To use the HAVING statement in the SQL language expand to the fuzzy aggregation query. Through the grouped data use aggregation operation to achieve the reduction of the data result set. And then in the fuzzy aggregation queries we lead into weight conception and put forward the fuzzy aggregation query with weight. It uses weight so as to express every condition relatively important degree in queries. It reflects different influence degree of the queries. This thesis realizes simple weighted fuzzy aggregation queries and queries with weight. It is analyzed that mechanism of getting rid of fuzzy on the fuzzy SQL statement. At last though experiments vivificate the validity of the fuzzy aggregation query. The work of this thesis can take advantage of the existing implementation mechanisms handled by the related databases. All the above research achievements will enrich and improve the theoretical system of fuzzy query to great extent.