我正在使用Rails 7.0.0和Ruby 3.0.3,同时使用gem 'acts-as-taggable-on', '~> 9.0'
。在这个环境下,通过安装全新的Rails应用程序后运行rails db:migrate
命令,我遇到了以下错误:
name@iMac project % rails db:migrate
== 20220105163513 ActsAsTaggableOnMigration: migrating ========================
-- create_table(:tags)
-> 0.0130s
-- create_table(:taggings)
-> 0.0085s
-- add_index(:taggings, :tag_id)
rails aborted!
StandardError: An error has occurred, this and all later migrations canceled:
PG::DuplicateTable: ERROR: relation "index_taggings_on_tag_id" already exists
/Users/name/here/project/db/migrate/20220105163513_acts_as_taggable_on_migration.acts_as_taggable_on_engine.rb:26:in `up'
Caused by:
ActiveRecord::StatementInvalid: PG::DuplicateTable: ERROR: relation "index_taggings_on_tag_id" already exists
/Users/name/here/project/db/migrate/20220105163513_acts_as_taggable_on_migration.acts_as_taggable_on_engine.rb:26:in `up'
Caused by:
PG::DuplicateTable: ERROR: relation "index_taggings_on_tag_id" already exists
/Users/name/here/project/db/migrate/20220105163513_acts_as_taggable_on_migration.acts_as_taggable_on_engine.rb:26:in `up'
我已经多次尝试使用新的Rails应用程序运行此操作,但是相同的错误一遍又一遍地出现。
以下内容位于/Users/name/here/project/db/migrate/20220105163513_acts_as_taggable_on_migration.acts_as_taggable_on_engine.rb文件中的第26行。
'class ActsAsTaggableOnMigration < ActiveRecord::Migration[6.0]
def self.up
create_table ActsAsTaggableOn.tags_table do |t|
t.string :name
t.timestamps
end
create_table ActsAsTaggableOn.taggings_table do |t|
t.references :tag, foreign_key: { to_table: ActsAsTaggableOn.tags_table }
t.references :taggable, polymorphic: true
t.references :tagger, polymorphic: true
t.string :context, limit: 128
t.datetime :created_at
end
add_index ActsAsTaggableOn.taggings_table, :tag_id
add_index ActsAsTaggableOn.taggings_table, %i[taggable_id taggable_type context],
name: 'taggings_taggable_context_idx'
end
def self.down
drop_table ActsAsTaggableOn.taggings_table
drop_table ActsAsTaggableOn.tags_table
end
end`
请参考GitHub上的这个问题:
rails new myapp --database=postgresql
命令来生成新的Rails应用程序。 - jgrantdb/migrate/20220105163513_acts_as_taggable_on_migration.acts_as_taggable_on_engine.rb
中添加了代码,因为rake db:migrate
没有成功,所以我还没有schema.rb
。 - jgrantt.references :tag, foreign_key: { to_table: ActsAsTaggableOn.tags_table }
应该创建add_index ActsAsTaggableOn.taggings_table, :tag_id
尝试添加的索引,但这应该早在 acts-as-taggable 中就出现了。尝试注释掉add_index ActsAsTaggableOn.taggings_table, :tag_id
行,重新运行迁移,然后再次执行\d
命令查看索引是否存在。 - mu is too shortadd_index ActsAsTaggableOn.taggings_table, :tag_id
注释掉并重新运行迁移以及在数据库上执行\d
命令,会得到以下输出:alt_development=# \d index_taggings_on_tag_id Index "public.index_taggings_on_tag_id" Column | Type | Key? | Definition --------+--------+------+------------ tag_id | bigint | yes | tag_id btree, for table "public.taggings"
@muistooshort - jgrant