September 2017
Intermediate to advanced
360 pages
9h 43m
English
Content preview from Architecting the Industrial Internet
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Query
A query enables the filtering and selection of data. Queries can be executed against a dataset by a user, by an addressable device (through web sockets), by an application, or through analytical, reporting, visualization, and other tools. Query results can be pushed to a gateway to provide a data source for higher level brokers.
Query models are typically one time or continuous. A one-time query involves selection of data in response to a request, while a continuous query produces a stream of data. One-time queries are used to return a single result set and are well suited for the publish-subscribe data pattern. Streaming data returns data in real-time or at prescribed intervals and can be used in tracking and monitoring real-time analytics ...