ruby on rails - PG::UndefinedColumn: ERROR: column comments.post_id does not exist -

i cant seem figure out why keep getting error. trying add comment forms blog making , wont work. here full error says.

activerecord::statementinvalid in posts#show

showing /users/ipbyrne/firstrailsapp/blog/app/views/posts/show.html.erb line #17 raised:

pg::undefinedcolumn: error: column comments.post_id not exist line 1: select count() "comments" "comments"."post_id" ... ^ : select count() "comments" "comments"."post_id" = $1

</p>     <div id="comments">        <h2><%= @post.comments.count %> comments</h2> <-- says breaks here        <%= render @post.comments %>         <h3>add comment:</h3> 

from can understand there column missing in 1 of tables in schema.rb file? incase case here mine looks like

# encoding: utf-8 # file auto-generated current state of database. instead # of editing file, please use migrations feature of active record # incrementally modify database, , regenerate schema definition. # # note schema.rb definition authoritative source # database schema. if need create application database on # system, should using db:schema:load, not running migrations # scratch. latter flawed , unsustainable approach (the more migrations # you'll amass, slower it'll run , greater likelihood issues). # # it's recommended check file version control system.  activerecord::schema.define(version: 20140911230918)    create_table "comments", force: true |t|     t.string   "name"     t.text     "body"     t.integer  "post_id"     t.datetime "created_at"     t.datetime "updated_at"   end    add_index "comments", ["post_id"], name: "index_comments_on_post_id"    create_table "posts", force: true |t|     t.string   "title"     t.text     "body"     t.datetime "created_at"     t.datetime "updated_at"   end    create_table "users", force: true |t|     t.string   "email",                  default: "", null: false     t.string   "encrypted_password",     default: "", null: false     t.string   "reset_password_token"     t.datetime "reset_password_sent_at"     t.datetime "remember_created_at"     t.integer  "sign_in_count",          default: 0,  null: false     t.datetime "current_sign_in_at"     t.datetime "last_sign_in_at"     t.string   "current_sign_in_ip"     t.string   "last_sign_in_ip"     t.datetime "created_at"     t.datetime "updated_at"   end    add_index "users", ["email"], name: "index_users_on_email", unique: true   add_index "users", ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true  end 

yes, you're missing field post_id on comment model, tell rails comments belong posts.

you can add generating migration command line so:

rails generate migration addpostidtocomments post:references rake db:migrate