The basic chart widget is nice for some quick diagrams but I would not even bother and go with a more powerful solution. Just as @waitz_sebastian said, openHAB offers to be flexible. My recommendation would be to use InfluxDB+Grafana from the beginning.
That said setting up InfluxDB and Grafana takes a few minutes.
@yves are you new with openHAB? Persistence is something like the next level and barely needed for the pure home automation aspect of things. On the other hand is what and how data is persisted highly dependent on the user, hence there can’t be a general all-satisfying solution.
Your question regarding the “Essz. Temperatur 1” makes me believe, that you did not yet understand how items and sitemaps work in openHAB.
I’d recommend to first get used to openHAB before looking into the persistence topic. Start here:
- Items: http://docs.openhab.org/configuration/items.html
- Sitemap: http://docs.openhab.org/configuration/sitemaps.html
- One easy example: Astro Items+Sitemap+Map+♈ Binding Example
Browse through the two documentation articles, then work your way through the astro example and tinker a bit. You’ll learn all you need to know in the process. Good luck!