Rails - Jul 2006 - How to create a child from a parent

Hi i am trying to figure out what is the best way to do this very basic 
thing:
lets say i have two tables: one with parents and one with children. 
there is a one to many relation between them.

I scaffolded the parents tabel and i can open each parent. Now i want to 
add a link to the ''show'' view which will create a new child
record.

In the model i defined the has_many and belongs_to relations between the 
children an parents but i dont know what i have to do in the controller 
part in order to fill the foreign key field of the child table.

in some example i saw in the controler someting like:

@parent = Parent.find(params[:id])
@child.parent = @parent
@child.save

but that doesn''t seem to work in my test application, the child saves 
but the foreign key is null

on the other hand, if i do
@child.parent_id=parent.id
that works but i am not sure that is the way to go, because for that i 
don''t have to define the relations in the model, this will work anyway

hope someone can give me some pointers for this very basic question

regards,

Remco

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remco hh wrote on 13.07.2006 10:20:
> Hi i am trying to figure out what is the best way to do this very basic 
> thing:
> lets say i have two tables: one with parents and one with children. 
> there is a one to many relation between them.
[...]
> in some example i saw in the controler someting like:
> 
> @parent = Parent.find(params[:id])
> @child.parent = @parent
> @child.save
> 
> but that doesn''t seem to work in my test application, the child
saves
> but the foreign key is null
> 
> on the other hand, if i do
> @child.parent_id=parent.id
> that works but i am not sure that is the way to go, because for that i 
> don''t have to define the relations in the model, this will work
anyway
I think you have a wrong association.
If childs table has a column parent_id then the child belongs_to parent.
If parents table has a column child_id then the child has_one parent.
But I think you want to do the first and then your found example works.