If you have already run your original migration (before editing it), then you need to generate a new migration (rails generate migration add_email_to_users email:string will do the trick). It will create a migration file containing line: add_column :users, email, string Then do a rake db:migrate and it’ll run the new migration, creating the new column. … Read more
I believe what you are looking for is assign_attributes. It’s basically the same as update_attributes but it doesn’t save the record: class User < ActiveRecord::Base attr_accessible :name attr_accessible :name, :is_admin, :as => :admin end user = User.new user.assign_attributes({ :name => ‘Josh’, :is_admin => true }) # Raises an ActiveModel::MassAssignmentSecurity::Error user.assign_attributes({ :name => ‘Bob’}) user.name # … Read more
I believe you can do this: gem “foo”, path: “/path/to/foo”
rails destroy controller lalala rails destroy model yadayada rails destroy scaffold hohoho Rails 3.2 adds a new d shortcut to the command, so now you can write: rails d controller lalala rails d model yadayada rails d scaffold hohoho
You won’t always be able to simply generate the migration to already have the code you want. You can create an empty migration and then populate it with the code you need. You can find information about how to accomplish different tasks in a migration here: http://api.rubyonrails.org/classes/ActiveRecord/Migration.html More specifically, you can see how to drop … Read more
I know two ways to do this: This will reset your database and reload your current schema with all: rake db:reset db:migrate This will destroy your db and then create it and then migrate your current schema: rake db:drop db:create db:migrate All data will be lost in both scenarios.
Rails has an except/except! method that returns the hash with those keys removed. If you’re already using Rails, there’s no sense in creating your own version of this. class Hash # Returns a hash that includes everything but the given keys. # hash = { a: true, b: false, c: nil} # hash.except(:c) # => … Read more
Use rand(range) From Ruby Random Numbers: If you needed a random integer to simulate a roll of a six-sided die, you’d use: 1 + rand(6). A roll in craps could be simulated with 2 + rand(6) + rand(6). Finally, if you just need a random float, just call rand with no arguments. As Marc-André Lafortune … Read more
It looks like in Ubuntu that header is part of the libpq-dev package (at least in the following Ubuntu versions: 11.04 (Natty Narwhal), 10.04 (Lucid Lynx), 11.10 (Oneiric Ocelot), 12.04 (Precise Pangolin), 14.04 (Trusty Tahr) and 18.04 (Bionic Beaver)): … /usr/include/postgresql/libpq-fe.h … So try installing libpq-dev or its equivalent for your OS: For Ubuntu/Debian systems: … Read more
rename_column :table, :old_column, :new_column You’ll probably want to create a separate migration to do this. (Rename FixColumnName as you will.): script/generate migration FixColumnName # creates db/migrate/xxxxxxxxxx_fix_column_name.rb Then edit the migration to do your will: # db/migrate/xxxxxxxxxx_fix_column_name.rb class FixColumnName < ActiveRecord::Migration def self.up rename_column :table_name, :old_column, :new_column end def self.down # rename back if you need … Read more