Question

I need some table like this one:

uid:integer
pid:integer
predesposition:integer
primary_key(uid,pid)
foreign_key(uid, user(id))
foreign_key(pid, user(id))

So, two questions:
1. How can I declare multiply FKs in migration?
2. How can I declare two (or more) columns belonged to same table in migration?

Example:

create_table :encounters, :id => false do |t|
  t.belongs_to :user, :polymorphic => true
  t.belongs_to :user, :polymorphic => true
  t.integer :predisposition
end

Answer 1

If you want to refrence other table then follow the concept of foreign key . And wanna to suggest to use full table name instead of uid and pid .

create_table :table_name, {:id => false} do |t|
  t.integer :user_id
  t.integer :pid #suppose its procedures table
  t.integer :predesposition
  t.references :user
  t.references :procedure
  t.timestamps
end
execute "ALTER TABLE table_name ADD PRIMARY KEY (user_id,pid);"

Hope that help .