在Rails中使用主键创建表和问题 [英] Creating tables and problems with primary key in Rails

问题描述

当我尝试使用Mysql2作为数据库管理器在Rails中运行以下代码时:

When I try to run the following code in Rails using Mysql2 as database manager:

rake db:migrate

我得到以下错误:

 rake aborted!
 "Mysql2::Error: All parts of a PRIMARY KEY must be NOT NULL:"

如果默认情况下表中的主键不是"null"，为什么会出现此错误?

Why do I get this error, if the primary key in a table by default is NOT "null"?

但是，迁移代码:

class CreateUsers < ActiveRecord::Migration
   def change
    create_table :users do |t|
     t.string "first_name"
     t.timestamps
    end
   end 
end

推荐答案

我之前也遇到过同样的问题，我根据这里解决了 https://github.com/rails/rails/pull/13247#issuecomment-32425844

I had a same problem before, and I solved according to here https://github.com/rails/rails/pull/13247#issuecomment-32425844

使用Rails 2.3.5，MySQL 5.7.9版本和mysql gem需要具备 此位用作初始化程序 config/initializers/abstract_mysql_adapter.rb:

With Rails 2.3.5, MySQL version 5.7.9 and mysql gem you need to have this bit as an initializer in config/initializers/abstract_mysql_adapter.rb:

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

对于mysql2，它应该是config/initializers/abstract_mysql2_adapter.rb:

For mysql2, it should be config/initializers/abstract_mysql2_adapter.rb:

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

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