Javabased
TinyDB Client API should be installed on Client, which is convenient
for users. Each node in the sensor network must be installed with the Sensor
Network Software (TinyQP). TinyDB Server accepts queries from client,
parses and decomposes them, then sends these queries to the related nodes in
the network. Of course, TinyDB server also receives query results and returns
them to clients.
Fig. 18. The Architecture of TinyDB [21].
The TinyDB system can be broadly classified into two subsystems: Sensor
Network Software and Client Interface. Sensor Network Software is the heart
of TinyDB, it runs on each mote in the network, and consists of several major
pieces:
1. Sensor Catalog and Schema Manager: The catalog is responsible
for tracking the set of attributes, or types of readings (e.g., light, sound,
voltage) and properties (e.g., network parent, node ID) available on each
sensor. In general, this catalog is not identical for each sensor: networks
may consist of heterogeneous collections of devices, and may be able to
report di?®erent properties.
2. Query Processor: The main component of TinyDB is a small query
processor. The query processor uses the catalog to fetch the values of
local attributes, receives sensor readings from neighboring nodes over the
radio, combines and aggregates these values together, filters out undesired
data, and outputs values to parents.
3. Memory Manager: TinyDB extends TinyOS with a small, handle-based
dynamic memory manager.
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