logical query meaning in English

逻辑查询

In order to query " the data in multimedia database , we present logical query lancuaee based on multimedia - instance model and demonstrate the applications of the logical query language by some examples
为查询多媒体数据库中的数据，我们给出了基于媒体实例模型的逻辑查询语言，并举例说明该语言的应用。
Many mature technologies on this level have been brought out , such as the relational algebra law , the improved logical query plan , the cost estimation of operation , the selective plan based on cost and order of joint , etc . although many methods have been tried out , no remarkable result or noteworthy technology has come to reality because of complexity of data decomposition and network effects
例如，从物理查询计划的底层磁盘输入输出到语法分析阶段的语法分析树、用于改进查询计划的代数定律、逻辑查询计划的改进，以及操作代价的估计、基于代价的计划和连接顺序的选择等全过程，都进行了不懈的努力。在这方面的研究已经非常成熟。