What Can Hierarchies Do for Data Streams?
نویسندگان
چکیده
Much effort has been put into building data streams management systems for querying data streams. Here, data streams have been viewed as a flow of low-level data items, e.g., sensor readings or IP packet data. Stream query languages have mostly been SQL-based, with the STREAM and TelegraphCQ languages as examples. However, there has been little work on supporting OLAP-like queries that provide multi-dimensional and summarized views of stream data. In this paper, we introduce a multidimensional stream query language and its formal semantics. Our approach enables powerful OLAP queries against data streams with dimension hierarchies, thus turning low-level data streams into informative high-level aggregates. A comparison with STREAM shows that our approach is more flexible and powerful for high-level OLAP queries, as well as far more compact and concise.
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