I have a system with a bunch of sensors on it. Originally I was using MySQL to organize the data using the following schema:
The important tables for this discussion are:
- Tag (caution: this is my own use of “tag” and shouldn’t be confused with InfluxDB definition)
- Tag usage
- Unit of measure (volt, celsius, etc.)
- Variable (temperature, pressure, etc.)
- Data point
A system must be modeled with one or more tags. A tag must be the source of a tag usage. A tag usage must be expressed in terms of a unit of measure, as well as a variable. A data point must come from a tag usage.
For example, consider a temperature sensor on the system. The tag “T1” would model that sensor in the database, and two tag usages could be 1=“actual temperature” and 2=“temperature setpoint”, with 1 and 2 being primary keys.
Therefore, data being inserted into the datapoint table would look like:
I’d like to use InfluxDB to store the time series data (i.e. the datapoint table) as that is what it is built to do. The documentation seems to be recommending that I store a tag “variable=temperature” with every data point representing a temperature measurement, etc. That seems like a violation of keeping a database in normal form and I would think that metadata would be stored elsewhere.
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EDIT 1: Add related questions.
EDIT 2: Change voltage to temperature in last paragraph.
EDIT 3: Add another related question.
EDIT 4: Add another related question.