Rails 未添加模型字段来插入查询
我通过迁移向 Rails 中的数据库添加了一列，并更新了 new.html.erb 以将该字段添加到表单中。
请求参数中包含正确的数据，但生成的插入查询每次该列的值为空。
这是请求参数：
{"commit"=>"Create",
"assignment"=>{"start_date"=>"08/04/2010",
"project_id"=>"5",
"allotment"=>"50",
"person_id"=>"33",
"end_date"=>"08/05/2010"},
"authenticity_token"=>"8f157a2a220caf716607162ce9557ab6505aab1a"}
这是显示空列的查询所产生的错误：
Mysql::Error: Column 'end_date' cannot be null:
INSERT INTO `assignments` (`start_date`, `created_at`, `project_id`, `updated_at`, `allotment`, `person_id`, `end_date`)
VALUES('2010-08-04', '2010-08-04 03:36:21', 5, '2010-08-04 03:36:21', 50, 33, NULL)
这是有问题的迁移：
class ChangeDates < ActiveRecord::Migration
def self.up
add_column :assignments, :end_date, :date, :null => false
rename_column :assignments, :date, :start_date
end
def self.down
remove_column :assignments, :end_date
rename_column :assignments, :start_date, :date
end
end
我无法弄清楚出了什么问题。我已经回滚并迁移了几次更改，但没有成功。我很困惑。
I've added a column to a db in rails via a migration, and updated new.html.erb to add the field to the form.
The correct data is in the request params, but the insert query that is generated has a null for the column every time.
Here are the request params:
{"commit"=>"Create",
"assignment"=>{"start_date"=>"08/04/2010",
"project_id"=>"5",
"allotment"=>"50",
"person_id"=>"33",
"end_date"=>"08/05/2010"},
"authenticity_token"=>"8f157a2a220caf716607162ce9557ab6505aab1a"}
and here is the resulting error with query showing the null column:
Mysql::Error: Column 'end_date' cannot be null:
INSERT INTO `assignments` (`start_date`, `created_at`, `project_id`, `updated_at`, `allotment`, `person_id`, `end_date`)
VALUES('2010-08-04', '2010-08-04 03:36:21', 5, '2010-08-04 03:36:21', 50, 33, NULL)
Here's the migration in question:
class ChangeDates < ActiveRecord::Migration
def self.up
add_column :assignments, :end_date, :date, :null => false
rename_column :assignments, :date, :start_date
end
def self.down
remove_column :assignments, :end_date
rename_column :assignments, :start_date, :date
end
end
I can't figure out what went wrong. I've rolled back and migrated the change a couple of times with no luck. I'm stumped.
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为了回答有关 attr_accessor 的问题，范围将在类方法之前调用访问器方法，因此将值保存到访问器，但是当调用保存时，它返回方法调用。我希望通过示例来澄清这一点： http://codepad.org/gAppUMc4
我也做了同样的事情几次。其超级令人沮丧。
To answer you question about attr_accessor, scope will call the accessors method before the class method, so were saving the value to the accessor, but when the save was called it was returning the method call. I hope this clarifies it by example: http://codepad.org/gAppUMc4
I've done the same thing several times. Its super frustrating.
如果您还没有这样做，请尝试重新启动您的网络服务器。 Rails 可能会缓存列名称。
您正在运行什么版本的 Rails 以及什么网络服务器？
If you haven't already, try restarting your webserver. Rails might be caching the column names.
What version of Rails and what webserver are you running?