Similar data in database

Hi, Is there a way to stop data entering the database if there is already the same thing in there. Say you are registering a vehicle with plate model and color. The plate should only be allowed once in the database. How would I do it.

You could try this action for the event that creates the new thing:

Create a new thing (the thing you want to create)

only when: Do a Search for the thing you want to create: count is 0