Using the `set` datatype in MySQL

I just came across a requirement of labeling a user as 1 of 3 different rol开发者_运维知识库es. Normally I have used an id, but the roles don't really relate to each other at all.

I had a look at the set datatype, and I added the 3 different options.

• Will the database internally just store the index of the set, e.g. if the set is set('a', 'b', 'c') and I choose a, will it store a or the index 0?

• I haven't seen this datatype used before when looking at other people's databases. Is it bad practice? Is using an id (perhaps role_id which maps to a table roles) a better idea?

Thanks

They're roles - that's how they relate to one another.