CODEWITHSUNDEEP
ruby-on-rails-3
Robert B
Robert B

Reputation: 2883

PG::Error: ERROR: null value in column "created_at" when inserting records into associated model

I have a Job model and a Category model which I've joined using a HABTM association.

I'm getting an error when trying to assign to Categories_Jobs model.

PG::Error: ERROR: null value in column "created_at" violates not-null constraint

j = Job.first
Job Load (0.7ms)  SELECT "jobs".* FROM "jobs" LIMIT 1
=> #<Job id: 7, user_id ...(removed rest of details for sake of clarity)

j.categories
Category Load (0.8ms)  SELECT "categories".* FROM "categories" INNER JOIN "categories_jobs" ON "categories"."id" = "categories_jobs"."category_id" WHERE "categories_jobs"."job_id" = 7
=> [] 

j.category_ids = [1]
Category Load (6.1ms)  SELECT "categories".* FROM "categories" WHERE "categories"."id" =   $1 LIMIT 1  [["id", 1]]
(0.2ms)  BEGIN
(0.6ms)  INSERT INTO "categories_jobs" ("job_id", "category_id") VALUES (7, 1)
(0.1ms)  ROLLBACK
ActiveRecord::StatementInvalid: PG::Error: ERROR:  null value in column "created_at" violates not-null constraint

Should I remove the timestamps from my Categories_Jobs model?

class CreateCategoriesJobs < ActiveRecord::Migration
  def change
    create_table :categories_jobs, :id => false do |t|
      t.integer :category_id
      t.integer :job_id
      t.timestamps
    end
  end
end

Should I be doing this another way?

Upvotes: 11

Views: 8802

Answers (4)

Maya Webster
Maya Webster

Reputation: 164

In case it helps anyone else, I ran into this error message when saving an object with child models. Inspecting the child models, I saw a parent id populated on them even though the parent model did not have an id. I turned on logging and found that the parent model was being rolled back because of an error in an after_create block.

Upvotes: 0

declan
declan

Reputation: 5635

My answer doesn't exactly answer the OP's question, but this post comes up when googling the error message so I'm answering anyway.

I've got a has_many relationship. Let's say we're using a Parent model, and Parent has_many :child_models.

When I call

@parent.child_models.create(params)

then Postgres complains about null values. But if I split it up everything is fine:

@child = @parent_object.child_models.build
@child.save

Another solution was to take out the NOT NULL constraint. In that case create returns without error, and when I look at the record later the timestamps are set. ActiveRecord must be saving the record without timestamps initially, and then going back and inserting them. (Rails 4.2.5)

Upvotes: 0

Nickolay Kondratenko
Nickolay Kondratenko

Reputation: 1951

Just use another kind of many-to-many relation declaration.

class Category ...

  has_many :categories_jobs
  has_many :categories, through: :categories_jobs

  ...
end

class Job ...

  has_many :categories_jobs
  has_many :jobs, through: :categories_jobs

  ...
end

then you will be able to use timestamps.

Upvotes: 6

Dipak Panchal
Dipak Panchal

Reputation: 6036

see below link for your solution.

HABTM

your solution

remove t.timestamps and then run.

class CreateCategoriesJobs < ActiveRecord::Migration
  def change
    create_table :categories_jobs, :id => false do |t|
      t.integer :category_id
      t.integer :job_id
    end
  end
end

Upvotes: 8

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