Hi-
Say I have a db with following schema:
MyTable: Id, name, user_id, date
User: id, name, description
I know that I want to add "belongs_to" in my "user" model but how can I enforce a proper constraint on the user_id in "MyTable"? Is this done using a has_one in the "MyTable" model?
Thanks!
Hello,
I think you're confusing things a bit.
With the tables you describe you should put the following into your models:
my_table.rb belongs_to :user
user.rb has_many :my_tables (or has_one :my_table)
If you want it the other way around, you should put the foreign key my_table_id in your User model.
Regards
how can I enforce a proper constraint on the user_id in "MyTable"?
If you mean constraints on a database level: you will have to put those in manually. AFAIK Rails itself (e.g. migrations) do not provide support for database level constraints of anything other than datatype (and length). There surely is a plugin around though..
- Niels.
Cool, this helps. One more clarification...since "MyTable" was a really bad example....
job_posting.rb belongs_to :user
user.rb has_many :job_postings
So, say I want to link a user to a job posting, a user can have many job postings but I want to make sure that the user being referenced is a real user. Is this the correct approach?
Thanks!
Yes, that should be fine, but maybe you should add:
user.rb has_many :job_postings, :dependent => :destroy
Now if your user record is deleted, all it's job postings are also removed from the DB. Otherwise there 's a big chance you 'll get nil-errors in your views (eg. when you try to display <%= job_posing.user.name %>)
Stijn
Great, thank you!