I see it is applicable to set a tag or attribute to a timeseries, but what is the difference between these two conception?
CodePudding user response:
'Tag' of a timeseies in Apache IoTDB is indexed, which can be a filter in WHERE clause (but connnot be a part of SELECT clause for now). While 'attribute' is some kind of annotation, which cannot be filtered during a query.
For a example, in a timeserie database for electricity devices, you can set the ownership of the timeseries as a tag, so that you can query devices of a specified owner.
For more detial, you can visit this page: https://iotdb.apache.org/UserGuide/Master/IoTDB-SQL-Language/DDL-Data-Definition-Language.html#tag-and-attribute-management