Strange Rails ActiveRecord Behavior - ruby-on-rails

Question

Can someone please explain why the following queries return diff results?
If I run a simple "last" query I get an object back.
>> j = Job.last
(1.6ms) SELECT sqlite_version(*)
Job Load (0.7ms) SELECT "jobs".* FROM "jobs" ORDER BY "jobs"."id" DESC LIMIT ? [["LIMIT", 1]]
=> #<Job id: 12, customer_id: 3, description: nil, shoot_start_date: "2020-11-25
00:00:00", shoot_end_date: "2020-11-26 00:00:00", submission_deadline: "2020-11-27
00:00:00", delivery_deadline: "2020-11-28 00:00:00", created_at: "2020-11-25 21:44:22",
updated_at: "2020-12-14 19:30:06", token: "fd2356c1-996b-4f95-b24a-8c92829af1fe", name:
"teesting">
And with this object I can get children as follows:
>> j.job_entries
JobEntry Load (0.7ms) SELECT "job_entries".* FROM "job_entries" WHERE
"job_entries"."job_id" = ? LIMIT ? [["job_id", 12], ["LIMIT", 11]]
=> #<ActiveRecord::Associations::CollectionProxy [#<JobEntry id: 8, entity_id: 12,
agency_id: 35, created_at: "2020-12-07 21:27:47", updated_at: "2020-12-07 21:27:47", job_id:
12, job_role_id: 8>, #<JobEntry id: 9, entity_id: 13, agency_id: 35, created_at: "2020-12-14
17:35:30", updated_at: "2020-12-14 17:35:30", job_id: 12, job_role_id: 7>]>
HOWEVER, when I run a method on my object which is the following code:
def self.getJobAndSubmissions(token)
Job.includes(job_entries: :images_attachments).where(:token => token)
end
I get the very same record with attachments:
>> j = Job.getJobAndSubmissions('fd2356c1-996b-4f95-b24a-8c92829af1fe')
Job Load (0.9ms) SELECT "jobs".* FROM "jobs" WHERE "jobs"."token" = ? LIMIT ? [["token",
"fd2356c1-996b-4f95-b24a-8c92829af1fe"], ["LIMIT", 11]]
JobEntry Load (0.2ms) SELECT "job_entries".* FROM "job_entries" WHERE
"job_entries"."job_id" = ? [["job_id", 12]]
ActiveStorage::Attachment Load (1.0ms) SELECT "active_storage_attachments".* FROM
"active_storage_attachments" WHERE "active_storage_attachments"."record_type" = ? AND
"active_storage_attachments"."name" = ? AND "active_storage_attachments"."record_id" IN (?,
?) [["record_type", "JobEntry"], ["name", "images"], ["record_id", 8], ["record_id", 9]]
=> #<ActiveRecord::Relation [#<Job id: 12, customer_id: 3, description: nil,
shoot_start_date: "2020-11-25 00:00:00", shoot_end_date: "2020-11-26 00:00:00",
submission_deadline: "2020-11-27 00:00:00", delivery_deadline: "2020-11-28 00:00:00",
created_at: "2020-11-25 21:44:22", updated_at: "2020-12-14 19:30:06", token: "fd2356c1-996b-
4f95-b24a-8c92829af1fe", name: "teesting">]>
But suddenly, child references no longer work.
>> j.job_entries
Traceback (most recent call last):
1: from (irb):4
Job Load (0.2ms) SELECT "jobs".* FROM "jobs" WHERE "jobs"."token" = ? LIMIT ? [["token",
"fd2356c1-996b-4f95-b24a-8c92829af1fe"], ["LIMIT", 11]]
JobEntry Load (0.1ms) SELECT "job_entries".* FROM "job_entries" WHERE
"job_entries"."job_id" = ? [["job_id", 12]]
ActiveStorage::Attachment Load (0.2ms) SELECT "active_storage_attachments".* FROM
"active_storage_attachments" WHERE "active_storage_attachments"."record_type" = ? AND
"active_storage_attachments"."name" = ? AND "active_storage_attachments"."record_id" IN (?,
?) [["record_type", "JobEntry"], ["name", "images"], ["record_id", 8], ["record_id", 9]]
NoMethodError (undefined method `job_entries' for #.
<Job::ActiveRecord_Relation:0x00005562db1258c0>)
Did you mean? entries
What the? Please help me understand why this is happening!

Answer 1

Job.last
will return an ActiveRecord object.
Job.includes(job_entries: :images_attachments).where(:token => token)
returns an ActiveRecord::Relation which means you can't call job_entries on it.
You can get an object with this code
# These do the same thing
Job.find_by_token(token)
Job.find_by(token: token)

Answer 2

NoMethodError (undefined method `job_entries' for #. <Job::ActiveRecord_Relation:0x00005562db1258c0>)
Note the error message is not for Job but for a Job::ActiveRecord_Relation.
#last returns a single Job. #where returns a set of Jobs stored in an ActiveRecord::Relation. Job::ActiveRecord_Relation is a relation specific to Job.
You can also see this in the returned value...
>> j = Job.getJobAndSubmissions('fd2356c1-996b-4f95-b24a-8c92829af1fe')
...
=> #<ActiveRecord::Relation [#<Job id: 12, ...]>