undefined method 'info' for nil:NilClass when running active record migration

问题

I am trying to run an active record migration but am receiving the following error:

undefined method 'info' for nil:NilClass

Here is the 2 lines of code in my rake task that runs the migration

ActiveRecord::Base.establish_connection(YAML::load(File.open('src/SupporterSync.Core/Database/Database.yml')))
ActiveRecord::Migrator.migrate('src/SupporterSync.Core/Database/Migrations', ENV["VERSION"] ? ENV["VERSION"].to_i : nil )

And here is my only migration class in the folder

class InitialMigration < ActiveRecord::Migration
  def self.up
    create_table :Accounts, :primary_key => :Id do |t|
      t.string :ListId, :limit => 36, :null => false
      t.string :Name, :limit => 31, :null => false
      t.string :FullName, :limit => 31, :null => false
      t.string :ParentListId, :limit => 36
    end
  end
  def self.down
    drop_table :Accounts
  end
end

And here is the trace statement:

** Invoke migrate (first_time)
** Execute migrate
rake aborted!
undefined method info' for nil:NilClass<br /> C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/migration.rb :473:inmigrate'
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/migration.rb :472:in each'<br /> C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/migration.rb :472:inmigrate'
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/migration.rb :400:in up'<br /> C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/migration.rb :383:inmigrate'
E:/Working/Code/WMF/SupporterSync/rakefile.rb:19
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in call'<br /> C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in execute'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in each'<br /> C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in execute'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:597:in invoke_with_call_c hain'<br /> C:/Ruby/lib/ruby/1.8/monitor.rb:242:in synchronize'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in invoke_with_call_c hain'<br /> C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:583:in invoke'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2051:in invoke_task'<br /> C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in top_level'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in each'<br /> C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in top_level'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in standard_exceptio n_handling'<br /> C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in top_level'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in run'<br /> C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in standard_exceptio n_handling'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in run'<br /> C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/bin/rake:31<br /> C:/Ruby/bin/rake:19:inload'
C:/Ruby/bin/rake:19

回答1:

I suggest following Rails' conventions and making your table + field names lowercase_and_underscored rather than CamelCasing. Some macros such as belongs_to look for the lowercase variants and by using them you make your life a lot easier. I'm sorry this does not quite answer your question.

Also, the primary key is "id" by default, so you don't need to set it.

Thirdly, migrations are usually run with rake db:migrate.

Lastly, the reason you're getting that error is that you're setting up ActiveRecord::Base and not defining a logger object on it, like Rails does for you when you run any task descending from :environment. For more information, see this line in the Rails source.

回答2:

I turned off active_record logger (config.active_record.logger = nil) and came across this problem. I solved it by adding a logger back:

config.active_record.logger=Logger.new(STDOUT)

I added the code to config/environment/xxx.rb.

来源：https://stackoverflow.com/questions/1719212/undefined-method-info-for-nilnilclass-when-running-active-record-migration