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我正在使用Rails 4.2.3和PostgreSQL数据库。我想编写一个迁移来更新我的外键之一,使其具有删除时级联约束,因此我创建了以下代码:
class UpdateForeignKeyAddOnDeleteConstraint < ActiveRecord::Migration
def change
remove_foreign_key :my_object_times, :my_objects
add_foreign_key :my_object_times, :my_objects, on_delete: cascade
end
end
$ rake db:migrate
== 20160525203028 UpdateForeignKeyAddOnDeleteConstraint: migrating ============
-- remove_foreign_key(:my_object_times, :my_objects)
-> 0.0454s
-- cascade()
rake aborted!
StandardError: An error has occurred, this and all later migrations canceled:
undefined local variable or method `cascade' for #<UpdateForeignKeyAddOnDeleteConstraint:0x007f82f2c71998>
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activerecord-4.2.5.1/lib/active_record/migration.rb:664:in `block in method_missing'
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activerecord-4.2.5.1/lib/active_record/migration.rb:634:in `block in say_with_time'
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activerecord-4.2.5.1/lib/active_record/migration.rb:634:in `say_with_time'
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activerecord-4.2.5.1/lib/active_record/migration.rb:654:in `method_missing'
最佳答案
您需要更改此行,
add_foreign_key :my_object_times, :my_objects, on_delete: cascade
add_foreign_key :my_object_times, :my_objects, on_delete: :cascade
cascade
应该是符号(
:cascade
)或字符串(
'cascade'
)。
关于ruby-on-rails-4 - 如何创建一个用删除时级联约束更新外键的Rails迁移?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/37447531/
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