(2) Query languages. For query of data stream
management system, with the general high-level language
such as C + + or Java as the main development and
programming tools can result in the long development cycle
and high maintenance cost. [3]In contrast, people prefer to
use such as SQL (structured query language) to deal with
the real-time data flow in a high-level language. SQL has a
group of powerful data processing primitives to deal with
filtration, merger, association and aggregation.