rails storing id's from reference table

When I submit a text field into user_items I want it to take the ID of that item from master_list_items and place it into the master_list_items_id column under user_items

I have added master_list_items.rb -- but I'm not sure of the relationship to add..

Any suggestions?

master_list_items

+----------------------+----+
| name                 | id |
+----------------------+----+       
| Item A               | 1  |
| Item B               开发者_运维技巧| 2  |
| Item C               | 3  |
+----------------------+----+  

user_items

+---- +----------+----------------------+
| uid | item     | master_list_item_id  |
+-----+----------+----------------------+
| 2   | Item A   | NULL                 |
| 7   | Item C   | NULL                 |
| 9   | Item C   | NULL                 |
+-----+----------+----------------------+  

I'm going to guess your models are done like this:

class MasterListItem < ActiveRecord::Base
    has_many :user_items
end

class UserItem < ActiveRecord::Base
    belongs_to :master_list_item
end

To implement what you're looking for the solution would probably be like this:

master_list_item = MasterListItem.create( :name => "Item 1" )
user_item = master_list_item.user_items.build( :name => "User Item 1" )
user_item.save

This should yield the results you're looking for.

For more on relationships refer to the associations module on ActiveRecord.