StreamAPAS: Query Language and Data Model

The system StreamAPAS and its declarative query language allows users to define temporal data analysis. This paper addresses the problem of lack of the continuous language standard. The proposed language syntax indicates how hierarchical data structures simplify working with spatial data and groups of tuple attributes. The query language is also based on object-oriented programming concepts as a result of which continuous processing applications are easier to develop and maintain. In addition, we discuss the problem of a query logic representation. In contrast to relations stored in DBMS, data streams are temporal so that DSMS should be aware of their dynamic characteristics.Streams characteristics can be described using variables such as tuple rates and invariables like monotonicity. In StreamAPAS, a query is represented as a directed acyclic graph (DAG), whose operators define tuple data transmission model and have information of result stream monotonicity associated with them. Even though this representation is still static,this approach enables us to detect optimization points which are crucial from a stream processing viewpoint.