It
also contains system commands and sub-routings used to query and update
the table. This table can contain any types of attributes. It can also contain
handles to a set of commands that can be run within the query executor,
much like ???methods??? in the Object-Relational extensions to SQL.
Sensor Catalog and Schema Manager consists of six major components:
Attr, Command, TinyDBAttr, TinyDBCommand, Tuple and QueryResult.
The Attr and Command components contain the code to manage the
schema of the mote. The Attr component implements interfaces for getting
and setting the values of attributes. The Command module includes the codes
to implement all the commands in the schema and provides the schema to invoke
the commands.
TinyDBAttr is the hub for all the built-in attributes of TinyDB. It wires
all the components that implement the built-in attributes together. This component
must be updated if you add a new component that implements new
attributes for TinyDB.
TinyDBCommand is the hub for all the built-in commands of TinyDB.
It wires all the components that implement the built-in commands together.
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Chapter 12 Data Management in Sensor Networks
This component must be updated if a new component that implements new
commands for TinyDB is added.
Tuple provides fairly straightforward utilities to manage the Tuple data
structure.
QueryResult converts between Tuples, QueryResults, and byte-strings. A
Tuple is a vector of values; a QueryResult holds a tuple and some metadata,
including the query ID, an index of the result set, etc.
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