[Rails/Postgres] DB migrate scripts break on references

[Joe Tseng]

I've been following online examples of how to create tables the Rails way
and I noticed the migration scripts I created containing references don't
work out of the box. I thought maybe I did something wrong so I tried just
now making a test application/migration against a *SQLite3* datasource. I
ran the following commands:

$ rails g scaffold SchoolClass name
$ rails g scaffold Student name SchoolClass:references

And it made my migration scripts (along with everything else).
[image: Inline image 1]

I ran the migration scripts and it worked fine.
[image: Inline image 3]

When I tried doing the same steps above against a *Postgres* datasource, I
kept on getting the following:

PG::UndefinedTable: ERROR: relation does not exist

The only way I got past this issue is if I went into the migration script
and updated the t.references line and replaced the class name with the
actual table name. It's a simple enough fix, but I've got a ton of tables
to migrate and each table can have a good number of references. Has anyone
seen this before, and is there some way to keep on using the scaffold
utility to make migrations?

Appreciative of any useful assistance,

- Joe

[botp]

Post by Joe Tseng
$ rails g scaffold SchoolClass name
$ rails g scaffold Student name SchoolClass:references

try using snake_case notation. eg,
bin/rails g scaffold school_class name
bin/rails g scaffold student name school_class:references

best regards --botp

[Andy Jones]

1) You should be able to use either CamelCase or under_scored in the “scaffold name” part of `rails generate scaffold NAME 
` .



2) Your problem comes from the fact you are using CamelCase to refer to the already existing table school_class. You can’t do that there, only in the scaffold name part when you first create it.



3) Just so you know: this isn’t a Rails mailing list.

From: ruby-talk [mailto:ruby-talk-***@ruby-lang.org] On Behalf Of Joe Tseng
Sent: 17 January 2017 20:05
To: Ruby users
Subject: [Rails/Postgres] DB migrate scripts break on references

I've been following online examples of how to create tables the Rails way and I noticed the migration scripts I created containing references don't work out of the box. I thought maybe I did something wrong so I tried just now making a test application/migration against a SQLite3 datasource. I ran the following commands:

$ rails g scaffold SchoolClass name
$ rails g scaffold Student name SchoolClass:references

And it made my migration scripts (along with everything else).
[Inline image 1]

I ran the migration scripts and it worked fine.
[Inline image 3]

When I tried doing the same steps above against a Postgres datasource, I kept on getting the following:


PG::UndefinedTable: ERROR: relation does not exist
The only way I got past this issue is if I went into the migration script and updated the t.references line and replaced the class name with the actual table name. It's a simple enough fix, but I've got a ton of tables to migrate and each table can have a good number of references. Has anyone seen this before, and is there some way to keep on using the scaffold utility to make migrations?

Appreciative of any useful assistance,

- Joe