Deleting Inputs

I have been using EmonCms for a long time, and quite large amounts of data have accumulated. I don’t want to lose this data. I’m cleaning up the database. I’ve seen that I don’t need some Inputs. If I delete these inputs, will it affect the database?
Will the old data be lost or are there problems with the data display?
Do I have to delete the corresponding feeds first before I delete the inputs?

Inputs are created automatically. If it says inactive it means it has not received any data for a while. If the data source still exists, if you delete the input, it will just reappear.

Feeds are the actual data stored. You can trim feeds if you wish (select one feed and then click on the dustbin item).

You can delete an inactive input and leave the historic data (the Feed) if you wish.