I'm trying to finalize my design of the data model for my project, and am having difficulty figuring out which way to go with it.

I have a table of users, and an undetermined number of attributes that apply to that user. The attributes are in almost every case optional, so null values are allowed. Each of these attributes are one to one for the user. Should I put them on the same table, and keep adding columns when attributes are added (making the user table quite wide), or should I put each attribute on a separate table with a foreign key to the user table.

I have decided against using the EAV model.

Thanks!