定位及通信技术的发展使获取和传输移动车辆的轨迹信息成为可能。从车辆轨迹数据中可以提取出大量的交通信息，这些信息是对交通状况的一个直接和全面的反映。但由于轨迹数据固有的网络特性及时空特性，使针对此类数据的查询成为一个难点，其中关键技术包括建立用于车辆轨迹数据的索引结构及其对应的轨迹数据查询语言。在比较现有轨迹数据索引结构的基础上，对轨迹数据查询语言的分类及其与索引结构之间的调用关系进行了初步的探讨，提出了面向连通关系的查询语言（connectivity-oriented query language, CQL）的定义、分类及实现方法，并简要讨论了车辆轨迹数据查询原型系统的结构和实现方法。

The advances in positioning and communication technologies make it possible to collect and transfer trajectories of moving vehicles. In addition to some basic applications such as navigation, traffic data can be extracted from vehicle trajectories, such as average moving velocity and travel time on a road segment in a given time period. The network and spatio-temporal characteristics of trajectories, however, make it difficult to evaluate queries applied to them. As a result, many studies have focused on developing index structures and methods for trajectory data. However, few of them have presented the corresponding data query language. In this paper, we discussed some issues related to trajectory data query language, including the definition of the connectivity-oriented data query language (CQL), the classification of CQL, and its implementation based on an index structure proposed by previous study. We further discussed a prototype for vehicle trajectory data query based on CQL in terms of its structure and implementation.