[SOLVED] Assign a value from one table to a value from another table and save it in a field.

In my application there is, among other things, the value " evidence object ". Each "evidence object" belongs to a "trace class", e.g. an "asservat=HDD" belongs to the trace class "computer system". Currently both values are selected from one selection table each, works perfectly.

How can I realize that, when selecting a value from the table "evidence object", the correct value is automatically entered in the field " trace class". There are approx. 20 "evidence objects", these are to be assigned altogether 6 "trace classes".

As an example:
"evidence object" / "trace class"

HDD/Computer Systems
PC/Computer System
Notebook/Computer Systems
Tablet/Tablet
Mobile phone/mobile phone
Navigation System/Navigation System

etc.

If HDD is selected as "evidence object", the value "Computer Systems" should be automatically entered in the field "trace class".

Thank you in advance