Mysql2 :: Error: all parts of the PRIMARY KEY must be NOT NULL; if you need NULL in the key, use UNIQUE instead

Question

I created a demo application in rails 3.2.9and ruby versiion 2.0.0. After creating a forest blog model, I try to migrate it, but I have the following problem.

# rake db: migrate

== CreateBlogs: migration ============================================= ================================================

- create_table (: blogs) rake interrupted!

StandardError: an error occurred, all subsequent migrations are canceled:

Mysql2 :: Error: all parts of the PRIMARY KEY must be NOT NULL; if you need NULL in the key, use UNIQUE instead: CREATE TABLE blogs( idint (11) DEFAULT NULL auto_increment PRIMARY KEY, titlevarchar (255), descriptiontext, created_atdatetime NOT NULL, updated_atdatetime NOT NULL) ENGINE = InnoDB / usr / local / rvm / gems / ruby -2.0.0-p648@demo-app /gems/activerecord-3.2.9/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:245:in query' /usr/local/rvm/gems/ruby-2.0.0-p648@demo-app/gems/activerecord-3.2.9/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:245:inblock in execute '/ usr / local / rvm / gems / ruby - 2.0.0-p648@demo-app / gems / activerecord -

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-3.2.9/lib/active_record/migration.rb: 551: migrate' /usr/local/rvm/gems/ruby-2.0.0-p648@demo-app/gems/activerecord-3.2.9/lib/active_record/railties/databases.rake:179:in (2 ) ' /usr/local/rvm/gems/ruby -2.0.0-p648@demo-app/gems/rake-11.3.0/exe/rake:27:in `' : TOP = > db: migrate (. , --trace)

Answer 1

//abstract_mysql2_adapter.rb

require 'active_record/connection_adapters/mysql2_adapter'

class ActiveRecord::ConnectionAdapters::Mysql2Adapter
  NATIVE_DATABASE_TYPES[:primary_key] = "int(11) auto_increment PRIMARY KEY"
end

Answer 2

id int(11) DEFAULT NULL auto_increment PRIMARY KEY ( ) NULL. ( schema.rb) , DEFAULT NULL .