User system database design

Question

I'm designing a database for a new project and I'm looking for some feedback on the design before I start to implement/test. It basically consists of users, events, user profiles and a messaging system.

Certain users can create events which others can view, this is determined from the userType table. I'm unsure if I should be storing the lost password columns in the users table, would there any benefit for using a separate table for this?

(I'm not to sure if my relationships are setup correctly)

Full size

Appreciate any feedback given =)

Thanks !

Answer 1

Having the users and lost passwords in the same table implies a 1-1 (or 1-0/1) relationship; 1 user has 1 lost password (or none, if the column is nullable).

If that's the cardinality of the relationship, having them on the same table is correct. The school of thought that refuses nulls (which depending on the day, I adhere to), says that if the relationship is 1-0/1, you should:

users
  usersID primary key

lostPasswords
  usersID primary key references users(users_id)
  -- lost password columns here, non-nullable

The relationships look fine, however, I would suggest you use a diagramming tool which shows which are the columns referenced. Surprisingly, I've only found SchemaSpy doing this: http://schemaspy.sourceforge.net/sample/diagrams/summary/relationships.real.compact.png