在该模型的基础上,还探讨了时态查询、房产动态变化分析等问题。
On the basic of model, this paper discusses the problems such as tense query and real estate dynamic change analysis.
GTSQL便是我们提出的一个时态查询语言。本文给出了GTSQL的主要语法。
Therefore, we give our temporal query language GTSQL, where its syntax is given.
涉及业务时间的时态查询也很容易编写,您仅需要在from子句中包含FOR BUSINESS_TIME。
Temporal queries involving business time are also easy to write-and you need only include FOR BUSINESS_TIME in the FROM clause.
DB 2依据时态表的开始和结束列中使用的数据类型,使用合适的where子句谓词自动重写查询。
DB2 automatically rewrites the queries with appropriate WHERE clause predicates depending on the data types used in the start and end columns of the temporal tables.
为了实现时态数据库管理系统,除了数据模型之外,还需要有一个时态数据库的查询语言。
In order to implement a temporal database management system, we have to set up a query language for the data model.
在时态XML索引领域,较多是在时态xml文档更新时产生一个新版本,需要遍历不同的版本才能完成查询处理,影响查询处理性能。
In temporal XML index areas, most of them generate a new version when updating temporal XML document and need to traverse different versions to complete query processing.
对于提高时态XML文档上的查询效率,传统的XML索引并不是很有效,可以说时态XML还缺乏一些专用的索引技术。
However, traditional XML indexes don't do a good job in improving the query efficiency of temporal XML documents. Consequently, it is essential to introduce some special indexing technology.
时态数据库扩展了传统的关系数据库,其中一个重要的扩展就是对于时态聚集查询的支持。
Temporal database systems extend traditional relational database systems. One important such extension is to support time-varying aggregation.
时态数据库扩展了传统的关系数据库,其中一个重要的扩展就是对于时态聚集查询的支持。
Temporal database systems extend traditional relational database systems. One important such extension is to support time-varying aggregation.
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