Designing a Trading Card Game

Hello all!

I am in the process of starting a trading card game with unity just to practice my programming skill with a project. The game is similar to magic the gathering but on a not so complicated scale. What i was contemplating and couldn't find an answer to it is, how should i go about programming the cards in order to have automatic effects.

What i mean is, when for example i activate a creature's ability the effect should be made by the program and not by the user manually. So in order to have many effects, should i structure the program:

1. Class Card and as a subclass each card of the game?

2. Class Card and each unit as an entry in an XML file?

3. Or a database ( i think this is the most inefficient way of doing it)

Thanks for considering this question and reading it :D