# Initialising has\_many through joins

**URL:** <https://www.ruby-forum.com/t/initialising-has-many-through-joins/173300>\
**Category:** Rails\
**Created:** [August 6, 2009, 12:22pm UTC](https://www.ruby-forum.com/t/initialising-has-many-through-joins/173300 "2009-08-06T12:22:06Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![mdaoust](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/dbc845/32.png) [@mdaoust](https://www.ruby-forum.com/u/mdaoust)\
**Post date:** [August 6, 2009, 12:22pm UTC](https://www.ruby-forum.com/t/initialising-has-many-through-joins/173300/1 "2009-08-06T12:22:06Z")

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Hi

What is the quick and tidy way to initialise has\_many through  
associations?

What I need is a form that edits the join so where no join exists a  
blank field is initialised. Now using accepts\_nested\_attributes\_for and  
fields for this is very tidy and easy for existing fields, but how do I  
initialise those joins as empty fields without saving them?

Something like

# model

order has\_many order\_items  
order has\_many items through order\_items

# controller

def edit  
@order = Order.find(params(id)  
@order.items.merge(Items.find(:all)) # something along these lines

TIA