Keep track of a date saving the old

Questions
1

I need idea for how to solve this in practise…
I have an Instrument database.
The user picks a date in the future where the next tjeck should be beformed (NextTjeckDate).
The old NextTjeckData I want to save to comparison later.

How do I best do this? Make a second DB storing the old NextTjeckDate’s?
Should I make one for each instrument?

2

Create a new Data Type called Tjeck. With a date and whatever else you need.
Create a field on the Instrument called Next Tjeck of Type Tjeck.
Create a field on the Instrument called TjeckHistory of Type Tjeck and tick the LIST box.

  1. Create a Tjeck. Set the Next Tjeck field to the Tjeck you just created.

  2. Create the NEXT Tjeck when you have Tjecked the Instrument. ADD the Next Tjeck to TjeckHistory. Set Next Tjeck to the next Tjeck you created at the start of this step.