I know the community has discussed several times about how to let IoTDB support
standard SQL [1]. A naive perspective is that if we can convert IoTDB into a
relational table schema, then we can use the ability of standard SQL to
represent richful query semantics.
The current idea is to take reference in Apache Druid, which allows users
define which column represents for the timestamp, which columns are dimensions
(equals to iotdb's time series path, except for the last level of the path),
and which are metrics (equals to iotdb's measurement)[2].
If there is such an interface to let users define the above info (Druid uses a
json to define that), then it is possible to transform the schema of IoTDB into
a relational model. This would further optimize the Apache Calcite integration
work previously attempt by the community, and enrich the query capacity of
IoTDB.
[1] https://lists.apache.org/thread/gwrm4rly3jsz7zyxm8bwhr1yy4g13x65
[2]
https://druid.apache.org/docs/0.22.1/ingestion/schema-design.html#time-series-model
