Question

When I submit Style create form I would like to create a new Style with a few Features. The features are chosen from a multi-select box which is populated from a features table in the database. The through table should update appropriately, depending on the features chosen from the multi-select.

I am able to do the following within rails console:

@style = Style.first
@style.feature_ids = ['','2','4','6']

After typing the above I will see my through table updated with three rows the appropriate style_id and feature_id.

In my Style create form I have the following:

<%= m.input :feature_ids, :label => "Features", :collection => @features, :input_html => { :multiple => true } %>

On submission of the form I receive the following PG error:

PG::Error: ERROR:  column "feature_id" is of type integer but expression is of type character varying at character 96
HINT:  You will need to rewrite or cast the expression.
: INSERT INTO "stylefeatures" ("created_at", "feature_id", "style_id", "updated_at") VALUES ($1, $2, $3, $4) RETURNING "id"

From the params hash:

{"utf8"=>"✓",
 "authenticity_token"=>"lkdI9jhlhPW1P2Tyb8jFMKFM/kVXvgcJfSkL0qNH7xk=",
 "style"=>{"name"=>"123",
 "feature_ids"=>["",
 "2",
 "4",
 "6"],
 "commit"=>"Create Style"}

Answer 1

Your @features is a collection of Strings, change it to integer and you’ll be good (that’s what your db’s complaining about).