Save record in rails 4.0 using params hash

Question

I'm trying to create a new record in rails using the form_for helper method. I think the params hash is blank because I keep getting blank errors when I submit the form.

This is my form:

<% provide(:title, "Add Department") %>
<h1>Add Department</h1>

<div class="row">
    <div class="span6 offset3">
        <%= form_for(@department) do |f| %>
            <%= render 'shared/department_error_messages' %>

            <%= f.label :Full_Department_Title %>
            <%= f.text_field :full_name %>

            <%= f.label :Department_Abbreviation %>
            <%= f.text_field :abbreviation %>

            <%= f.submit "Add department", class: "btn btn-large btn-primary" %>
        <% end %>
    </div>
</div>

This is my departments controller

class DepartmentsController < ApplicationController
    def show
        @department = Department.find(params[:id])
    end

    def new
        @department = Department.new
    end

    def create
        @department = Department.new(params[department_params])     # Not the final implementation!
        if @department.save
            redirect_to root_path
        else
            render 'new'
        end
    end

    private

    def department_params
        # This says that params[:department] is required, but inside that, only params[:department][:full_name] and 
        # params[:department][:abbreviation] are permitted. Unpermitted params will be stripped out         

        params.require(:department).permit(:full_name, :abbreviation)
    end
end

This is the Model:

class Department < ActiveRecord::Base
    validates :full_name, presence: true, length: { minimum: 6 }
end

When I submit, errors are rendered saying the full_name can't be blank (and the fields are now empty). The debug info is:

--- !ruby/hash:ActionController::Parameters utf8: ✓ 
authenticity_token: EjfYjWAzaw7YqVZAkCPZwiEMFfb2YLIRrHbH1CpZOwA= 
department: !ruby/hash:ActionController::Parameters   
full_name: Sports Department   
abbreviation: SD 
commit: Add department 
action: create 
controller: departments

I've also checked the development log. The transaction starts and is then rolled back. I can save a record in the console so I'm guessing its something to do with the params hash, but can't figure it out. Please help

Answer 1

This line:

@department = Department.new(params[department_params])

Should be:

@department = Department.new(department_params)

And, as a minor issue (but not causing this problem), your label tags should look like:

f.label :full_name, "Full Department Title"

This way they are correctly associated with the input.