Ruby-on-rails 如何删除 ActiveRecord 对象？

How do you delete an ActiveRecord object?

提问by Blankman

How do you delete an ActiveRecord object?

如何删除 ActiveRecord 对象？

I looked at Active Record Queryingand it does not have anything on deleting that I can see.

我查看了Active Record Querying，它没有任何我可以看到的删除内容。

1. Delete by id,

2. Delete the current object like: user.remove,

3. Can you delete based on a whereclause?

1. 删除id,

2. 删除当前对象，如：user.remove,

3. 您可以根据where子句删除吗？

回答by Marek Sapota

It's destroyand destroy_allmethods, like

它destroy和destroy_all方法，比如

user.destroy
User.find(15).destroy
User.destroy(15)
User.where(age: 20).destroy_all
User.destroy_all(age: 20)

Alternatively you can use deleteand delete_allwhich won't enforce :before_destroyand :after_destroycallbacks or any dependent association options.

或者，您可以使用deleteand delete_all，它不会强制执行:before_destroy和:after_destroy回调或任何相关的关联选项。

User.delete_all(condition: 'value')will allow you to delete records without a primary key

User.delete_all(condition: 'value')将允许您删除没有主键的记录

Note: from @hammady's comment, user.destroywon't work if User model has no primary key.

注意：来自@hammady 的评论，user.destroy如果用户模型没有主键，则不起作用。

Note 2: From @pavel-chuchuva's comment, destroy_allwith conditions and delete_allwith conditions has been deprecated in Rails 5.1 - see guides.rubyonrails.org/5_1_release_notes.html

注 2：来自@pavel-chuchuva 的评论，Rails 5.1 中不推荐使用destroy_all条件和delete_all条件 - 请参阅 guides.rubyonrails.org/5_1_release_notes.html

回答by nonopolarity

There is delete, delete_all, destroy, and destroy_all.

有delete，delete_all，destroy，和destroy_all。

The docs are: older docsand Rails 3.0.0 docs

文档是：旧文档和Rails 3.0.0 文档

deletedoesn't instantiate the objects, while destroydoes. In general, deleteis faster than destroy.

delete不会实例化对象，而destroy会。一般来说，delete比 快destroy。

回答by Tadas T

1. User.destroy

1. User.destroy

User.destroy(1)will delete user with id == 1and :before_destroyand :after_destroycallbacks occur. For example if you have associated records

User.destroy(1)将删除用户与id == 1和:before_destroy和:after_destroy出现回调。例如，如果您有关联的记录

has_many :addresses, :dependent => :destroy

After user is destroyed his addresses will be destroyed too. If you use delete action instead, callbacks will not occur.

用户被销毁后，他的地址也将被销毁。如果您改用删除操作，则不会发生回调。

1. User.destroy, User.delete

2. User.destroy_all(<conditions>)or User.delete_all(<conditions>)

2. User.destroy, User.delete

3. User.destroy_all(<conditions>)或者 User.delete_all(<conditions>)

Notice: User is a class and user is an instance object

注意：用户是一个类，用户是一个实例对象