rails-migrations

I am using Rails 3.2.6 and Mysql 6.0.9 (but I have exactly the same error on MySQL 5.2.25) When I create new database ( rake db:create ) and then when I try to load the schema ( rake schema:load ) I get this error: Mysql2::Error: Specified key was too long; max key length is 767 bytes: CREATE UNIQUE INDEX `unique_schema_migrations` ON `schema_migrations` (`version`) After hours and hours of research I found these solutions: 1. Change MySQL variable innodb_large_prefix to true (or ON) This didn't work. I tried it on my Linux server, my Mac and even on Windows - it just doesn't work. 2.

I'm writing a migration to add a column to a table. The value of the column is dependent on the value of two more existing columns. What is the best/fastest way to do this? Currently I have this but not sure if it's the best way since the groups table is can be very large. class AddColorToGroup < ActiveRecord::Migration def self.up add_column :groups, :color, :string Groups = Group.all.each do |g| c = "red" if g.is_active && is_live c = "green" if g.is_active c = "orange" g.update_attribute(:type, c) end end def self.down end end It's generally a bad idea to reference your models from your

I'm using rails 3.2.6 and I need to create a database VIEW. As usual I created a migration and I tried to achieve the goal using the execute method. Unfortunately the migration generates a table, not a view. Why? Many thanks in advance, Mauro UPDATE: I would like to have something as follows: class CreateMyView < ActiveRecord::Migration def self.up execute <<-SQL CREATE VIEW my_view AS SELECT ... SQL end def self.down execute <<-SQL DROP VIEW my_view SQL end end Unfortunately this migration creates a table... UPDATE: the previous code works! I was executing rake db:reset instead of rake db

How can I assign different table name with adding foreign key. for e.g I have a model like class MyPost < ActiveRecord::Base has_many :comments, class_name: PostComment end class PostComment < ActiveRecord::Base belongs_to :post, class_name: MyPost end Now i want to change my migration file like this: class CreatePostComments < ActiveRecord::Migration def change create_table :post_comments do |t| t.belongs_to :post, index: true t.timestamps null: false end add_foreign_key :post, :class_name => MyPost end end But it is not working. Migration is getting cancelled. How do I change my migration

The Rails guides to active record migrations says that you can do change_column_default :products, :approved, from: true, to: false I've got a change method in Rails that's similar to the following: change_column_default :people, :height, from: nil, to: 0 with the intention of going from not having any defaults, to having a default of zero. However, when I try rolling it back, I get ActiveRecord::IrreversibleMigration: ActiveRecord::IrreversibleMigration Considering I give Rails a from and to , why isn't it accepting it? I'm using Rails 4.2.0. if you are using mysql as adapter, then according