在Ruby on Rails中自动递增非主键字段
问题描述：
在RoR迁移中，如何自动增加非主键字段？我想在数据库定义中，而不是在模型中。
In a RoR migration, how do I auto increment a non-primary-key field? I'd like to do this in the db definition, and not in the model.
答
您需要执行SQL语句。
You need to execute an SQL statement.
statement = "ALTER TABLE `users` CHANGE `id` `id` SMALLINT( 5 ) UNSIGNED NOT NULL AUTO_INCREMENT"
ActiveRecord::Base.connection.execute(statement)
您可以在迁移中手动输入
you can entry manually in your migration
注意这只是一个例子。最终的SQL语句语法取决于数据库。
Note this is just an example. The final SQL statement syntax depends on the database.