Ok.. So I've got my initial table structures setup and I was hoping I could have associations help me out with something akin to embedded/nested objects but without the direct nesting (unless there's another way to achieve that goal)..
So, I've got an Address class that looks like the following :
class CreateAddresses < ActiveRecord::Migration
belongs_to :user
def self.up
create_table :addresses do |t|
t.string :address
t.string :city
t.string :state
t.string :zip
t.string :email
t.string :phone
t.timestamps
end
end
def self.down
drop_table :addresses
end
end
You don’t have a FK for user_id in your ADDRESSES table for starters, and you didn’t include your model files, so there’s no way of knowing whether you’ve defined the relationships there.
See:
http://guides.rubyonrails.org/migrations.html
http://guides.rubyonrails.org/association_basics.html
Ok.. So I've got my initial table structures setup and I was hoping I could have associations help me out with something akin to embedded/nested objects but without the direct nesting (unless there's another way to achieve that goal)..
So, I've got an Address class that looks like the following :
class CreateAddresses < ActiveRecord::Migration
belongs_to :user
The belongs_to definition should be in the model class not the migration.
def self.up
create_table :addresses do |t|
t.string :address
t.string :city
t.string :state
t.string :zip
t.string :email
t.string :phone
t\.timestamps
end
end
def self.down
drop_table :addresses
end
end
I've then got a user class that looks like the following :
class CreateUsers < ActiveRecord::Migration
has_one :address
Ditto for has_one
Colin
Thanks guys! I’ll play with this some more when I come home this evening…
One more question if I could… If I get the plumbing all plugged in as needed, do I ned to do
anything in particular with the view for the address object to get it to show up when adding or
editing a user record or will it get pulled in automagically? Just curious. Thanks!
I’m still trying to figure this all out in my head!
Thanks guys! I'll play with this some more when I come home this evening..
One more question if I could.. If I get the plumbing all plugged in as needed, do I ned to do
anything in particular with the view for the address object to get it to show up when adding or
editing a user record or will it get pulled in automagically? Just curious. Thanks!
accepts_nested_attributes_for is your friend for this one.
Fred
Ok.. Still working on this stuff.. I've got the t.reference in the migration for the address class and moved the belongs_to and has_one in the model classes as indicated (I didn't notice that!).
I noticed in the association-basics that I should be putting a create_table function (if that's what
it's called) in the CreateUsers class for Migrations but I'm concerned about doing that since I'll be using the address class on more than just the 'users' class -- does it really belong there or ??
Perhaps I'm overthinking this.. ??
Below are the two class definitions for both the model & migration :
class Address < ActiveRecord::Base
belongs_to :user
belongs_to :organization
belongs_to :supplier
end
class CreateAddresses < ActiveRecord::Migration
def self.up
create_table :addresses do |t|
t.string :address
t.string :city
t.string :state
t.string :zip
t.string :email
t.string :phone
t.references : users
t.timestamps
end
end
def self.down
drop_table :addresses
end
end
Are you not using generators for the initial creation of your model and migration source files? I’m asking because I think I can count on one hand the number of times I’ve ever written out a create_table function myself. Your inputs from the command line should do all this for you along with some of the work of setting up your model associations (e.g. the belongs_to call in your Address class definition) and save you some effort. If you’re using the generators properly, you may never have to touch the migration files for simpler applications.
rails g scaffold user acctLocked:boolean familyId:integer isProfileSetup:boolean …
rails g model address user:references address:string city:string …
For more info:
http://guides.rubyonrails.org/getting_started.html
http://guides.rubyonrails.org/command_line.html#rails-generate
One other small thing: you’re writing your variable names using camel case (lowerCaseWithCapitalsIndicatingWordBoundaries) whereas the more widely recognized Ruby convention is to use all_lower_case_with_underscores. I left your variable names as-is in the sample code above, but if it’s code that anyone else will ever see or work on, you might consider changing it.
Thanks for the reply Chris…
I’ll switch away from Camelcase… I use that at work all day long (C++) so I’m used to looking at
it.
I initially used the generator but when revising tables it didn’t want to run anymore complaining
some of the files were already there – which is why I resorted to hand-edits. I’ll do some more
reading on what you suggested… Thx!
– Rick
If you want to do revisions on existing tables (adding columns, changing data types, etc.) you can use migrations for that as well. Experiment on the command line with patterns like:
rails g migration add_columns_to_addresses column_1:string column_2:integer …
rails g migration remove_columns_from_addresses column_1:string column_2:integer …
The generator will try to figure out what you’re attempting to do if you give it some basic instructions and if what you want to do isn’t too complicated.
Thanks! I just realized I’ve got the “destroy” feature at my disposal and that I’ve got a LOT of
reading ahead of me!
I’m thinking I’ll just blow things away and recreate until I find what I’m looking for and it works
as expected. That might be easiest to ensure that the migrations don’t bite me since this is just
the VERY early stages of an application…
– Rick
Chris –
one more question if you don’t mind too much! So, I blew away everything and started over this
time using just the command line tools w/o fiddling around (at least outside of adding the enum
pieces – which seem on the surface like they might plug into the generator)… Below are the commands I use and works (sort-of) when using the web-interface to http://localhost:3000/users/new
However, I don’t believe it’s creating the associations correctly – the “has_one” is incorrect as it’s
kicked out when issuing the initial migrate to setup the database… Do I need to put the has_one
in by hand or is my syntax messed up? I was looking over the api-docs and thought i had it right
but perhaps not. Below are the commands I issued :
-
rails new test
-
rails generate scaffold user address:has_one acct_locked:boolean family_id:integer is_profile_setup:boolean last_login:datetime password:string security_question:string security_answer:string username:string type:string
-
rails generate model address user:references street:string city:string state:string zip:string email:string phone:string
-
bundle exec rake db:migrate
I get this on step #4 above :
rake aborted!
An error has occurred, this and all later migrations canceled:
undefined method `has_one’ for #ActiveRecord::ConnectionAdapters::TableDefinition:0x007fd88525e148
/Users/nrf/.rvm/gems/ree-1.8.7-2011.03/gems/activerecord-3.0.9/lib/active_record/connection_adapters/abstract/schema_definitions.rb:326:in `method_missing’
Ugg…
Chris --
one more question if you don't mind too much! So, I blew away everything and started over this
time using just the command line tools w/o fiddling around (at least outside of adding the enum
pieces -- which seem on the surface like they might plug into the generator).. Below are the commands I use and works (sort-of) when using the web-interface tohttp://localhost:3000/users/new
However, I don't believe it's creating the associations correctly -- the "has_one" is incorrect as it's
kicked out when issuing the initial migrate to setup the database.. Do I need to put the has_one
in by hand or is my syntax messed up? I was looking over the api-docs and thought i had it right
but perhaps not. Below are the commands I issued :
1) rails new test
2) rails generate scaffold user address:has_one acct_locked:boolean family_id:integer is_profile_setup:boolean last_login:datetime password:string security_question:string security_answer:string username:string type:string
3) rails generate model address user:references street:string city:string state:string zip:string email:string phone:string
4) bundle exec rake db:migrate
has_one doesn't belong in your migration/scaffold stuff. Add it to the
model later on. (belongs_to/references is the exception to this,
because user belongs_to :blah actually requires adding a column to the
users table whereas user has_one :blah doesn't)
Fred
One of my favorite phrases on this mailing list: “Yeah, what Fred said.” Migrations store information about your database, models store information about your classes, even though the differences right now might not be completely clear. Associations require a foreign key to map to (e.g. as denoted by “references” or actually creating an integer column with an appropriate name) on one of your tables, and the bidirectional relationships should be set up in your models (e.g. subclasses of ActiveRecord::Base).
Another small protip if I can offer it: never name anything “test” as you’ve done with your application. It’s not a reserved word, there’s no specific restriction against it, but I’ve had any number of situations where things started behaving strangely as a result of naming some thing in my application using a term that already has a meaning.