earticle

영어

In Object-Oriented Databases (OODB), nested object queries are used regularly. Nested structures are put in conditional expressions of the queries in two forms: nested sub-queries or path expression containing hidden joins – nested predicates in WHERE clauses. For nested queries, when analyzing the estimated cost of the nested algebraic expression, the expression evaluation result gives out an ineffective cost. Therefore, our method proposed in this paper will resolve the problems by leveling nested sub-queries in the nested queries. This method will increase the effectiveness of the query processing cost – We use object connection hypergraphs to present nested queries.