seeds.rb rails db:seed not working

Question

所以我的seeds.rb文件中有以下内容：

pop_culture = Category.create(category_name: 'Pop Culture')
sports = Category.create(category_name: 'Sports')
tazos = Category.create(category_name: 'Tazos')
woolworths = Category.create(category_name: 'Woolworths')
Subcategory.create(subcategory_name: 'AFL', category: sports)
Subcategory.create(subcategory_name: 'NRL', category: sports)
Subcategory.create(subcategory_name: 'Basketball', category: sports)
Subcategory.create(subcategory_name: 'Baseball', category: sports)
Subcategory.create(subcategory_name: 'Cricket', category: sports)
Subcategory.create(subcategory_name: 'Ninja Turtles', category: pop_culture)
Subcategory.create(subcategory_name: 'Pokemon', category: pop_culture)
Subcategory.create(subcategory_name: 'Final Fantasy', category: pop_culture)
Subcategory.create(subcategory_name: 'Marvel Cards', category: pop_culture)
Subcategory.create(subcategory_name: 'DC', category: pop_culture)
Subcategory.create(subcategory_name: 'Yu-gi-oh', category: pop_culture)
Subcategory.create(subcategory_name: 'Looney Tunes', category: tazos)
Subcategory.create(subcategory_name: 'Cheetahs', category: tazos)
Subcategory.create(subcategory_name: 'Star Wars', category: tazos)
Subcategory.create(subcategory_name: 'Simpsons', category: tazos)
Subcategory.create(subcategory_name: 'Space Jam', category: tazos)
Subcategory.create(subcategory_name: 'Dreamworks', category: woolworths)
Subcategory.create(subcategory_name: 'Disney Dominoes', category: woolworths)
Subcategory.create(subcategory_name: 'Marvel Discs', category: woolworths)

当我在终端中运行db:seed时，它会抛出错误：

轨道中止！活动模型：：缺少属性错误：无法写入未知 属性category_id/var/lib/gems/2.3.0/gems/activerecord-5.0.2/lib/active_record/attribute.rb：182：inwith_value_from_database' /var/lib/gems/2.3.0/gems/activerecord-5.0.2/lib/active_record/attribute_set.rb:53:inwrite_from_user'/var/lib/gems/2.3.0/gems/activerecord-5.0.2/lib/active_record/attribute_methods/write.rb：50：inwrite_attribute_with_type_cast' /var/lib/gems/2.3.0/gems/activerecord-5.0.2/lib/active_record/attribute_methods/write.rb:32:in write_attribute'/var/lib/gems/2.3.0/gems/activerecord-5.0.2/lib/active_record/attribute_methods.rb：361：in[]=' /var/lib/gems/2.3.0/gems/activerecord-5.0.2/lib/active_record/associations/belongs_to_association.rb:76:in replace_keys'/var/lib/gems/2.3.0/gems/activerecord-5.0.2/lib/active_record/associations/belongs_to_association.rb：14：inreplace' /var/lib/gems/2.3.0/gems/activerecord-5.0.2/lib/active_record/associations/singular_association.rb:22:in 作家'/var/lib/gems/2.3.0/gems/activerecord-5.0.2/lib/active_record/associations/builder/association.rb：119：incategory=' /var/lib/gems/2.3.0/gems/activemodel-5.0.2/lib/active_model/attribute_assignment.rb:46:in public_send'/var/lib/gems/2.3.0/gems/activemodel-5.0.2/lib/active_model/attribute_assignment.rb：46：in_assign_attribute' /var/lib/gems/2.3.0/gems/activemodel-5.0.2/lib/active_model/attribute_assignment.rb:40:in 块在_assign_attributes'/var/lib/gems/2.3.0/gems/activemodel-5.0.2/lib/active_model/attribute_assignment.rb：39：ineach' /var/lib/gems/2.3.0/gems/activemodel-5.0.2/lib/active_model/attribute_assignment.rb:39:in _assign_attributes'/var/lib/gems/2.3.0/gems/activerecord-5.0.2/lib/active_record/attribute_assignment.rb：26：in_assign_attributes' /var/lib/gems/2.3.0/gems/activemodel-5.0.2/lib/active_model/attribute_assignment.rb:33:in assign_attributes'/var/lib/gems/2.3.0/gems/activerecord-5.0.2/lib/active_record/core.rb：319：ininitialize' /var/lib/gems/2.3.0/gems/activerecord-5.0.2/lib/active_record/inheritance.rb:65:in 新'/var/lib/gems/2.3.0/gems/activerecord-5.0.2/lib/active_record/inheritance.rb：65：innew' /var/lib/gems/2.3.0/gems/activerecord-5.0.2/lib/active_record/persistence.rb:33:in create'/home/vic/railsapps/Swap_Deck/db/seeds.rb：12：in<top (required)>' /var/lib/gems/2.3.0/gems/activesupport-5.0.2/lib/active_support/dependencies.rb:287:inload'/var/lib/gems/2.3.0/gems/activesupport-5.0.2/lib/active_support/dependencies.rb：287：inblock in load' /var/lib/gems/2.3.0/gems/activesupport-5.0.2/lib/active_support/dependencies.rb:259:inload_dependency'/var/lib/gems/2.3.0/gems/activesupport-5.0.2/lib/active_support/dependencies.rb：287：inload' /var/lib/gems/2.3.0/gems/railties-5.0.2/lib/rails/engine.rb:549:in load_seed'/var/lib/gems/2.3.0/gems/activerecord-5.0.2/lib/active_record/tasks/database_tasks.rb：268：inload_seed' /var/lib/gems/2.3.0/gems/activerecord-5.0.2/lib/active_record/railties/databases.rake:196:in 块(2 级)在 '/var/lib/gems/2.3.0/gems/railties-5.0.2/lib/rails/commands/rake_proxy.rb：14：inblock in run_rake_task' /var/lib/gems/2.3.0/gems/railties-5.0.2/lib/rails/commands/rake_proxy.rb:11:in run_rake_task'/var/lib/gems/2.3.0/gems/railties-5.0.2/lib/rails/commands/commands_tasks.rb：51：inrun_command!' /var/lib/gems/2.3.0/gems/railties-5.0.2/lib/rails/commands.rb:18:in '/home/vic/railsapps/Swap_Deck/bin/rails：9：inrequire' /home/vic/railsapps/Swap_Deck/bin/rails:9:in'/var/lib/gems/2.3.0/gems/spring-2.0.1/lib/spring/client/rails.rb：28：inload' /var/lib/gems/2.3.0/gems/spring-2.0.1/lib/spring/client/rails.rb:28:in 呼叫'/var/lib/gems/2.3.0/gems/spring-2.0.1/lib/spring/client/command.rb：7：incall' /var/lib/gems/2.3.0/gems/spring-2.0.1/lib/spring/client.rb:30:in跑'/var/lib/gems/2.3.0/gems/spring-2.0.1/bin/spring：49：in<top (required)>' /var/lib/gems/2.3.0/gems/spring-2.0.1/lib/spring/binstub.rb:31:in load'/var/lib/gems/2.3.0/gems/spring-2.0.1/lib/spring/binstub.rb：31：in<top (required)>' /home/vic/railsapps/Swap_Deck/bin/spring:15:in ' 箱/轨：3：load' bin/rails:3:in' 任务：TOP => db：seed(通过使用 --trace 运行任务来查看完整跟踪)

那么，有什么需要解决的吗？我可以让它只播种类别并且有效，但我也需要子类别，因为我希望它们在我的网站上下拉。

多年来，我一直试图让这个愚蠢的东西发挥作用，但我无法理解整个类别/子类别的事情。

类别和子类别的迁移代码：

class CreateCategories < ActiveRecord::Migration[5.0]
def change
create_table :categories do |t|
t.integer :category_id
t.string :category_name
t.references :subcategory_id, foreign_key: true
t.timestamps
end
end
end
class CreateSubcategories < ActiveRecord::Migration[5.0]
def change
create_table :subcategories do |t|
t.integer :subcategory_id
t.string :subcategory_name
t.references :category_id, foreign_key: true
t.timestamps
end
end
end

Answer 1

轨中止！活动模型：：缺少属性错误：无法写入未知 属性category_id

该错误告知您在表中缺少category_id属性subcategories。 确保您有它来修复错误。

Answer 2

看看你的种子，我假设一个类别可以有多个子类别。

在这种情况下，您的迁移应为：

class CreateCategories < ActiveRecord::Migration[5.0]
def change
create_table :categories do |t|
t.string :category_name
t.timestamps
end
end
end

class CreateSubcategories < ActiveRecord::Migration[5.0]
def change
create_table :subcategories do |t|
t.string :subcategory_name
t.references :category, foreign_key: true
t.timestamps
end
end
end

您无需指定category_id和subcategory_id，因为迁移将自动生成名为 id 的主键列。

此处指定了如何使用迁移的完整详细信息

并且您的模型应该是：

class Category < ApplicationRecord
has_many :subcategories
end
class Subcategory < ApplicationRecord
belongs_to :category
end

此外，我建议您将category_name重命名为name，将subcategory_name重命名为name。前缀的使用是多余的。

Answer 3

在seeds.rb文件内的迁移之前添加以下行

Category.reset_column_information
Subcategory.reset_column_information