Rails seed.rb can't find table that exists in schema and SQL

Question

Class is a reserved word, so I have changed the table name from class_assignment to cassignments to avoid any chance that that is the error causing it (despite me having class_instruction(s). I have tried plural and singular versions, and still get the error. The cassignments table is a middle table for the many to many relationship between assignments and class_instructions.

Schema :

ActiveRecord::Schema.define(:version => 20130524160107) do

  create_table "assignments", :force => true do |t|
    t.string   "name"
    t.string   "fractionRepresentations"
    ....etc...
    t.datetime "created_at",                  :null => false
    t.datetime "updated_at",                  :null => false
  end

  create_table "cassiggnments", :force => true do |t|
    t.integer  "class_instruction_id"
    t.integer  "assignment_id"
    t.datetime "created_at",           :null => false
    t.datetime "updated_at",           :null => false
  end

  add_index "cassiggnments", ["assignment_id"], :name => "index_class_assignment_on_assignment_id"
  add_index "cassiggnments", ["class_instruction_id"], :name => "index_class_assignment_on_class_instruction_id"

  create_table "class_instructions", :force => true do |t|
    t.string   "name"
    t.datetime "time"
    t.datetime "created_at", :null => false
    t.datetime "updated_at", :null => false
    t.integer  "person_id"
  end

  add_index "class_instructions", ["person_id"], :name => "index_class_instructions_on_person_id"

  ....etc....

end

Trying to seed the db in the seed.rb

# ClassInstruction Assignment
  cia1 = Cassignment.create({ class_instruction_id: 4, assignment_id: 1 }, :without_protection => true ).save!

and I get the error:

rake aborted!
Could not find table 'cassignments'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/activerecord-3.2.2/lib/active_record/connection_adapters/sqlite_adapter.rb:465:in `table_structure'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/activerecord-3.2.2/lib/active_record/connection_adapters/sqlite_adapter.rb:346:in `columns'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/activerecord-3.2.2/lib/active_record/connection_adapters/schema_cache.rb:12:in `block in initialize'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/activerecord-3.2.2/lib/active_record/model_schema.rb:228:in `yield'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/activerecord-3.2.2/lib/active_record/model_schema.rb:228:in `default'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/activerecord-3.2.2/lib/active_record/model_schema.rb:228:in `columns'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/activerecord-3.2.2/lib/active_record/model_schema.rb:243:in `column_defaults'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/activerecord-3.2.2/lib/active_record/base.rb:479:in `initialize'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/activerecord-3.2.2/lib/active_record/persistence.rb:44:in `new'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/activerecord-3.2.2/lib/active_record/persistence.rb:44:in `create'
/Users/special/dev/SoundOfFractions/db/seeds.rb:83:in `<top (required)>'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/activesupport-3.2.2/lib/active_support/dependencies.rb:245:in `load'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/activesupport-3.2.2/lib/active_support/dependencies.rb:245:in `block in load'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/activesupport-3.2.2/lib/active_support/dependencies.rb:236:in `load_dependency'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/activesupport-3.2.2/lib/active_support/dependencies.rb:245:in `load'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/railties-3.2.2/lib/rails/engine.rb:520:in `load_seed'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/activerecord-3.2.2/lib/active_record/railties/databases.rake:309:in `block (2 levels) in <top (required)>'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:246:in `call'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:246:in `block in execute'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:241:in `each'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:241:in `execute'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:184:in `block in invoke_with_call_chain'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:177:in `invoke_with_call_chain'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:205:in `block in invoke_prerequisites'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:203:in `each'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:203:in `invoke_prerequisites'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:183:in `block in invoke_with_call_chain'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:177:in `invoke_with_call_chain'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:170:in `invoke'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/activerecord-3.2.2/lib/active_record/railties/databases.rake:252:in `block (2 levels) in <top (required)>'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:246:in `call'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:246:in `block in execute'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:241:in `each'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:241:in `execute'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:184:in `block in invoke_with_call_chain'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:177:in `invoke_with_call_chain'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/task.rb:170:in `invoke'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/application.rb:143:in `invoke_task'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/application.rb:101:in `block (2 levels) in top_level'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/application.rb:101:in `each'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/application.rb:101:in `block in top_level'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/application.rb:110:in `run_with_threads'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/application.rb:95:in `top_level'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/application.rb:73:in `block in run'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/application.rb:160:in `standard_exception_handling'
/Users/special/.rvm/gems/ruby-1.9.3-p362/gems/rake-10.0.4/lib/rake/application.rb:70:in `run'
/Users/special/.rvm/gems/ruby-1.9.3-p362/bin/ruby_noexec_wrapper:14:in `eval'
/Users/special/.rvm/gems/ruby-1.9.3-p362/bin/ruby_noexec_wrapper:14:in `<main>'
Tasks: TOP => db:setup => db:seed

The only strange thing is that despite my migrations, I didn't get a cassignment.rb model, so I had to manually create that (maybe I didn't use scaffold, what I am normally used to doing, but I digress). So for posterity, here is the cassignment.rb

class Cassignment < ActiveRecord::Base
  belongs_to :class_instruction
  belongs_to :assignment
end

naming pluralization matches other many to many relationship tables, and seed structures, but I have no clue where I am going wrong, other than the understanding that the seed file can't find the table, that does exist according to the sqlite browser, and is correctly called cassignments (plural).

Answer 1

You've created a table called cassiggnments with two 'g's

Answer 2

Is this a has_and_belongs_to_many relationship or a has_many :through relationship?

HABTM only: In the former case you don't need the model and it's important that the table name be both of the joining table names in alphabetical order. assignments_class_instructions

In both cases, the correct approach to creating a join is to add instances of one class to instances of the other rather than creating the joins directly.

class_instruction = ClassInstruction.find(4)
class_instruction.assignments << Assignment.find(1)

Also, there is no problem with class_assignments and ClassAssignment as table and model names, so that isn't the issue.