On Nov 17, 8:43 am, Daniel Bush <[EMAIL PROTECTED]> wrote:
> On Nov 17, 5:45 pm, abusiek <[EMAIL PROTECTED]> wrote:
>
>
>
> > Hi!
>
> > I'm struggling with this for a while and i'm new to rails so it's
> > quite frustrating ;)
>
> > I need to create new model object based on old one with only few
> > changes.
>
> > I have desings -> has many -> lines -> has_many -> fields
>
> > I've got input from user in array like this:
>
> > field =>[
> > line_id =>[ fiel_id => field_value]
> > ]
>
> > so I iterate:
>
> > input[:field].each do |line_id, line|
> > line.each do |field_id, field_value|
> > design.lines.find(line_id).fields.find(field_id).value =
> > field_value
> > design.lines.find(line_id).fields.find(field_id).something =
> > field_value
> > end
> > end
>
> You're finding stuff and assigning new values to what was found but
> not saving these changes back to the db as far as I can tell here.
> Retrieve the field once
> field=design.lines.find(line_id).fields.find(field_id)
> update its values and then save it
> field.something = ...
> field.save (or field.save!)
> You're not creating anything new, just updating old.
>
> If you want a new field, you'll need to create it:
> design.lines.find(line_id).fields.push(Field.new({hash-of-
> attributes}))
> This will add a new field to design's line with line_id.
>
> You could probably do something like
> new_field=Field.new(field.attributes)
> to create a new field with the same attributes as the existing
> 'field', alter
> its values as required and then push it onto the fields collection:
> design.lines.find(line_id).fields.push(Field.new(new_field))
>
> Be careful with names like 'field' - I don't know if they'll clash
> with rails names.
> Maybe also consider not chaining all those 'finds' together in one
> line.
> Find each thing and store it in a local variable or an instance
> variable so
> you won't have to get it again during the action.
>
> --
> Daniel Bush
I followed your suggestion and write this code:
1 new_design = Design.new design.attributes
2 design.background.colour_id = 123
3 new_design.background = Background.new
design.background.attributes
4 lines = design.lines
5 for line in lines
6 new_line = Line.new line.attributes
7 fields = line.fields
8 for field in fields
9 field.value = input_data[:field][line.id][field.id]
10 new_field = Field.new field.attributes
11 new_line.fields.push(new_field)
12 end
13 new_design.lines.push(new_line)
14 end
and now I'v got error that i have nil object in line 5, 8, 9 so it'
seems that rails think's design has no lines.
but when I type debug (lines) after line 4 it prints me some lines ...
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