CAJ | 학술논문

通过将UMQL查询的各类条件式映射为UMQA的对应代数算子,给出从UMQL多媒体查询到UMQA查询计划的等价转换算法,为任意UMQL查询生成等价的内部UMQA查询计划.然后,为了有效改善UMQA查询计划的执行代价,研究了等价UMQA代数变换规则和一般性优化策略,给出UMQA内部计划的优化算法.该算法基于等价规则变化UMQA查询计划,并使优化后的查询计划尽可能符合优化策略.最后,讨论了UMQA查询计划的逻辑执行方法,即UMQA代数算子的逻辑执行方法,以便从多媒体数据库中获取用户感兴趣的目标数据.这些算法均在一个UMQL原型系统中实现,且应用效果表明这些查询处理技术均切实可行.
통과장UMQL사순적각류조건식영사위UMQA적대응대수산자,급출종UMQL다매체사순도UMQA사순계화적등개전환산법,위임의UMQL사순생성등개적내부UMQA사순계화.연후,위료유효개선UMQA사순계화적집행대개,연구료등개UMQA대수변환규칙화일반성우화책략,급출UMQA내부계화적우화산법.해산법기우등개규칙변화UMQA사순계화,병사우화후적사순계화진가능부합우화책략.최후,토론료UMQA사순계화적라집집행방법,즉UMQA대수산자적라집집행방법,이편종다매체수거고중획취용호감흥취적목표수거.저사산법균재일개UMQL원형계통중실현,차응용효과표명저사사순처리기술균절실가행.
Through the mapping from UMQL (unified multimedia query language) conditional expressions to UMQA (unified multimedia query algebra) query operations, a translation algorithm from a UMQL query to a UMQA query plan is put forward, which can generate an equivalent UMQA internal query plan for any UMQL query.Then, to improve the execution costs of UMQA query plans effectively, equivalent UMQA translation formulae and general optimization strategies are studied, and an optimization algorithm for UMQA internal query plans is presented.This algorithm uses equivalent UMQA translation formulae to optimize query plans, and makes the optimized query plans accord with the optimization strategies as much as possible.Finally, the logic implementation methods of UMQA plans, i.e., logic implementation methods of UMQA operators, are discussed to obtain useful target data from a multimedia database.All of these algorithms are implemented in a UMQL prototype system.Application results show that these query processing techniques are feasible and applicable.