Data base planning advice?

[StarLion]

I’m going to quote my own post from… 4 years ago, about designing a database;

@StarLion

My general database design steps are three:

1: Identify Entities (User, Picture, Comment, etc) [These will be your main tables]
2: Identify Properties of the Entities (User’s Name, Email, etc) [These will be fields in your tables]
3: Identify Relationships Between Entities (A Comment is posted by a User) [These will be Foreign Keys and/or Join Tables]

Or more wordily: What are you storing information about, what information are you storing about them, and what ties do they have to each other.

A User is an entity. An activity is an entity [You can choose to have activities as a separate table if you want, but the table is going to be fairly small, as there is little information inherent to an activity from your description.]
A user has many properties. [An activity only has one intrinsic property - a name.]
A user performs an activity. This represents a relationship between them of a many-to-many variety, which [in the advanced implications of step 3] suggests there is a table to be had between the two. (this would be the second table felgall refers to)