How many types of NoSQL DB have in NR? And which is better for sensor data gathering (SQL or NoSQL)?
I don't think anyone keeps a count.
Have a search on flows.nodered.org and see what's there.
It depends more what you want to do with the data after you have stored it.
Lots of people suggest InfluxDB is worth using, particular it you want to do time series queries.
I found this
Can you tell me more about what i can to do with the data after i have stored it? What options i have?
Exactly why are you interested in a nosql database in particular?
Isn't that something you need to decide? Why are you collecting the data? Do you just want to display it somewhere? (Dashboard??) Do you want it to cause some other action? Do you just want to collect it because you can?
I want to build a weather station, and to store the sensor data for further analyze. And since i'm new to the DB sphere, i wish to explorer all the options, in order to make the best choice .
There are really many options.
Have you already thought about how many sensor readings per time interval you want to store?
If you look at influxdb (as mentioned), it seems that it might be overpowered for such a simple application of storing weather data. However, if you start doing some calculations, you very quickly realize that even if you just want to store sensor readings ever 5 minutes or so, you will end up with a lot of data very quickly.
Influxdb provides mechanisms to deal with that, for example, you can downsample old data etc.
But the most compelling advantage of influxdb compared to other databases is that many people use it exactly for the purpose of storing sensor readings, which means tools like https://grafana.com/ enable you to easily create a dashboard from an influxdb (grafana also has plugins for other types of databases).
However, if you come from an SQL background, influxdb can be a bit confusing first, since it seems very similar to SQL, but in reality isn't
One caveat of influxdb: Version 2 is in development at the moment, which is quite different to version 1, but currently, version 2 does not run on raspberries
I still not figured out the details.
I will try the Influxdb + grafana, if it don't work i will try something else.
What do you think about mongoDB?
First you want to know about the available nosql nodes, but you don't know what it means, you are "new to the DB sphere" - what is the reason for a nosql database ?
If the purpose is just a weather station, any type of storage would suffice, including a simple csv or text file.
But let's say you receive reasonable amounts of data from this weatherstation, what are the most important elements of the data that you will receive: The datapoint and the timestamp of that datapoint.
The key strengths of a NOSQL database is in scalability, high availability, key/value pairs, document stores.
The key strength of a RDBMS database is in it's relationship features.
The key strength of influxdb is in the middle of those 2 and has features of both, but it's primary goal is to gather time(series) driven data.
I want to try all options and than to decide what to do.
I've searched in the net for example of how to set up the influxdb, grafana and sensors in NR, but can't find enough simple example. Can you help me?
Start by studying the influx docs to find how the database works, then you can use the node-red-contrib-influxdb node to write the values to the database.
I'm looking for both practice and theory.
I don't understand, did influxdb create local DB like sqlite, or is more like mysql?
Watch some videos about it.
influx can be queried similar to a sqldb, but you don't have to create the structure. Which is why i stated above that influx has features of both nosql and rdbms.
That's why I said study the docs (theory) then have a play with the nodes (practice) to write to the database.
You do need to install influxdb server but the database can be local.
I learn faster via practical examples, but OK. Is there docs for influxdb in this NR site, because i don't find one?
There are a bunch on example flows with influxdb on the flows.nodered.org site
The docs for Influxdb itself (as opposed to how to use it in node-red) can be found at https://docs.influxdata.com/influxdb/v1.8/
Stick with 1.8 for the moment. There is an upcoming version 2.0 but it is still very new and not well supported yet.
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