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Diffstat (limited to 'railties/doc')
| -rw-r--r-- | railties/doc/guides/source/form_helpers.txt | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/railties/doc/guides/source/form_helpers.txt b/railties/doc/guides/source/form_helpers.txt index 7fb01bbf48..05f1b205db 100644 --- a/railties/doc/guides/source/form_helpers.txt +++ b/railties/doc/guides/source/form_helpers.txt @@ -403,6 +403,14 @@ As before, if you were to use `select` helper on a form builder scoped to `@pers <%= f.select(:city_id, ...) %> ---------------------------------------------------------------------------- +[WARNING] +============================= +If you are using `select` (or similar helpers such as `collection_select`, `select_tag`) to set a `belongs_to` association you must pass the name of the foreign key (in the example above `city_id`) and not the name of association itself. Active Record will raise an error along the lines of +-------- +ActiveRecord::AssociationTypeMismatch: City(#17815740) expected, got Fixnum(#1138750) +-------- +when you pass the params hash to `Person.new` or `update_attributes` if you specify `city` instead of `city_id`. Another way of looking at this is that form helpers only edit attributes. +============================ Option tags from a collection of arbitrary objects ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |