基于JDO查询语言的数据查询

介绍了JDO查询语言的必需组成部分和Query接口中的核心方法。通过一个应用实例讨论了JDO查询的过程以及Query接口中方法的应用,该实例包括一个简单查询和一个复杂查询。特别分析了JDO查询过滤器语义与Java语义在方法调用等方面的区别。最后概述了新的JDO规范在提高JDOQL效率方面所做的改进。

Data Query Based on JDO Query Language

The necessary components of JDO Query Language and the core methods in interface Query are introduced. Discusses the processes of JDOQL and application of the methods in Query with an application example, the example includes a simple query and a complex query. Especially, describes the differences between Java and JDOQL on syntax. At last, summarizes the new JDO speci- fication' s enhancements on improving JDOQL' s efficiency.