ENUM and SET column types member changes

[Ken Gillett]

This is not about how great or evil they are, just a specific question about their use.

I was under the impression that if you edit the list of ‘members’, existing data (i.e. the underlying numbers actually stored) would be unchanged and so might no longer then display the same text because the list of members is now different. But...

I was just looking into this with a SET column and adding new members, anywhere, kept existing data displaying exactly as before, but with the new members now available to be used. So..

The alteration of the member list caused MySQL to restructure the existing data to ensure that column still displayed the same text as before the change.

Was I simply wrong before, and MySQL has always done this or is it a new feature and can I assume ENUMs will receive the same treatment when changing the members list as for SET type columns?

I realise I could test it myself, but would appreciate this all being confirmed by those more experienced with MySQL than me.