I have an User entity that has a Set of Address where Address is a value object:

class User{
    ...
    private Set<Address> addresses;
    ...
    public setAddresses(Set<Address> addresses){
        //set all addresses as a batch
    }
    ...
}

A User can have a home address and a work address, so I should have something that acts as a look up in the database:

tbl_address_type

------------------------------------------------
|    address_type_id       | address_type      |
------------------------------------------------
|            1             |      work         |
------------------------------------------------
|            2             |      home         |
------------------------------------------------

and correspondingly tbl_address

-------------------------------------------------------------------------------------
|    address_id       |     address_description      |address_type_id|    user_id   |
-------------------------------------------------------------------------------------
|          1          |      123 main street         |      1        |      100     |
-------------------------------------------------------------------------------------
|          2          |      456 another street      |      1        |      100     |
-------------------------------------------------------------------------------------
|          3          |      789 long street         |      2        |      200     |
-------------------------------------------------------------------------------------
|          4          |      023 short street        |      2        |     200      |
-------------------------------------------------------------------------------------

1. Should the address type be modeled as an Entity or Value type? and Why?
2. Is it OK for the Address Value object to hold a reference to the Entity AdressType (in case it was modeled as an entity)? Is this something feasible using Hibernate/NHibernate?
3. If a user can change his home address, should I expose a User.updateHomeAddress(Address homeAddress) function on the User entity itself? How can I enforce that the client passes a Home address and not a work address in this case? (a sample implementation is most welcomed)
4. If I want to get the User's home address via User.getHomeAddress() function, must I load the whole addresses array then loop it and check each for its type till I found the correct type then return it? Is there a more efficient way than this?