Primary key non default name

Rails
1

Hi,

Is there a way when using scaffolding to name a primary key like
tablename_id instead of the default id?

Thanks,

Kostas

2

You could do this:

script/generate scaffold player player_id:primary_key name:string

which generates a migration like this

class CreatePlayers < ActiveRecord::Migration
def self.up
create_table :players do |t|
t.primary_key :player_id
t.string :name

  t.timestamps
end

end

def self.down
drop_table :players
end
end

Regards,
Craig

3

Thanks for the answer. I run:
script/generate scaffold reservation reservation_id:primary_key
name:string

followed by

rake db:migrate

and I get the following error:

== 20080830212120 CreateReservations: migrating

– create_table(:reservations)
rake aborted!
Mysql::Error: Incorrect table definition; there can be only one auto
column and it must be defined as a key: CREATE TABLE reservations
(id int(11) DEFAULT NULL auto_increment PRIMARY KEY,
reservation_id int(11) DEFAULT NULL auto_increment PRIMARY KEY,
reservation_name varchar(255) DEFAULT NULL NULL, created_at
datetime DEFAULT NULL NULL, updated_at datetime DEFAULT NULL NULL)
ENGINE=InnoDB

Apparently it tries to create two primary keys and fails.

Kostas

On Aug 30, 9:31 pm, “Craig D.” [email protected]

4

On 30 Aug 2008, at 22:23, samson78 wrote:

Thanks for the answer. I run:
script/generate scaffold reservation reservation_id:primary_key
name:string

you need create_table :players, :id => false do |t| …

so that rails doesn’t try to create its primary key as well as your own.

Fred

5

Thanks for the answer.
I did that and the migration completed fine.
Bit when I am trying to view the site it doesn’t show the edit, show,
destroy links, but only the “new” one. And the Create new doesn’t
work.

Kostas

On Aug 30, 10:33 pm, Frederick C. [email protected]

6

On 30 Aug 2008, at 23:01, samson78 wrote:

Thanks for the answer.
I did that and the migration completed fine.
Bit when I am trying to view the site it doesn’t show the edit, show,
destroy links, but only the “new” one. And the Create new doesn’t
work.

have you got set_primary_key in your model ?

Fred

7

The whole thing seems that has a problem with:

1)The params:id in the controller
do I leave it as :id or do I write the new primary key,
e.g. :reseravations_id

2)in the routes.rb

map.connect ‘:controller/:action/:id’
map.connect ‘:controller/:action/:id.:format’

It cannot get route as it searches for :id

Kostas

On Aug 30, 10:33 pm, Frederick C. [email protected]

8

Yes, the primary key is set when I use reservation_id:primary key when
calling the generate script
After db:migrate it shows as primary key on the database.

Kostas

On Aug 30, 11:38 pm, Frederick C. [email protected]

9

On 30 Aug 2008, at 23:15, samson78 wrote:

The whole thing seems that has a problem with:

1)The params:id in the controller
do I leave it as :id or do I write the new primary key,
e.g. :reseravations_id

should be able to leave it as :id - the primary key is always
available as id (ie the id method always exists and will return the
correct value)

Fred

2)in the routes.rb

map.connect ‘:controller/:action/:id’
map.connect ‘:controller/:action/:id.:format’

It cannot get route as it searches for :id

10

Well, you see this problem remains even when I use generate model and
then manually fill the migration with
t.primary_key:tablename_id
It tries to create a separate id.
And if I use :id =>false, so it creates only the tablename_id, I have
the same problems as I mentioned above.

Kostas

11

Out of sheer curiosity, what’s the compelling reason to ditch Rails’
convention and change the primary key if you’re still using
scaffolding?

RSL

12

I meant, what’s the compelling reason to not go with Rails’ defaults
and use the :id field? If you’re not using a legacy database and all.
Most people who need/want to change the primary key are doing so
because they are having to support a legacy db with columns already
created. You seem to be creating this database for the first time and
it’s usually a good idea to go with Rails’ defaults then, unless
there’s a compelling reason not to. Which is what I was asking. :slight_smile:

RSL

13

Oh right,

I am cerating the database for the first time, but I am trying to
imitate an existing database (for testing purposes).
Because the old app works with the existing database and unfortunately
parts of the old app will continue to exist for some time alongside
the new components that will be done with RoR.Messy, I know, but not
my decision!!

Thanks,

Kostas