ruby-on-rails - 问题将数据库迁移到 Heroku - PG::UndefinedTable: ERROR: relation "users"does not exist

Question

对于初学者，我使用两个不同的数据库，开发中的 sqlite 和生产中的 postgresql。

我认为这个问题与我的数据库更改后忘记不断迁移到 heroku 有关。在迁移到 heroku 之前，我可能在本地进行了四到五次迁移。所以无论如何，问题是当我 tun heroku run rails db:migrate 我收到一条错误消息说 PG::UndefinedTable: ERROR: relation "users"does not exist 虽然在开发中它确实如此。我会尝试在下面附上所有必要的信息。如果有任何遗漏，请告诉我。

架构.rb

# This file is auto-generated from the current state of the database. Instead
# of editing this file, please use the migrations feature of Active Record to
# incrementally modify your database, and then regenerate this schema definition.
#
# Note that this schema.rb definition is the authoritative source for your
# database schema. If you need to create the application database on another
# system, you should be using db:schema:load, not running all the migrations
# from scratch. The latter is a flawed and unsustainable approach (the more migrations
# you'll amass, the slower it'll run and the greater likelihood for issues).
#
# It's strongly recommended that you check this file into your version control system.

ActiveRecord::Schema.define(version: 20161011053831) do

  create_table "comments", force: :cascade do |t|
    t.integer  "user_id"
    t.text     "body"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.integer  "post_id"
    t.index ["post_id"], name: "index_comments_on_post_id"
    t.index ["user_id"], name: "index_comments_on_user_id"
  end

  create_table "posts", force: :cascade do |t|
    t.string   "title"
    t.text     "body"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

  create_table "users", force: :cascade do |t|
    t.string   "first_name"
    t.string   "last_name"
    t.datetime "created_at",                          null: false
    t.datetime "updated_at",                          null: false
    t.string   "email",                  default: "", null: false
    t.string   "encrypted_password",     default: "", null: false
    t.string   "reset_password_token"
    t.datetime "reset_password_sent_at"
    t.datetime "remember_created_at"
    t.integer  "sign_in_count",          default: 0,  null: false
    t.datetime "current_sign_in_at"
    t.datetime "last_sign_in_at"
    t.string   "current_sign_in_ip"
    t.string   "last_sign_in_ip"
    t.index ["email"], name: "index_users_on_email", unique: true
    t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
  end

end

终端输出

Running rails db:migrate on ⬢ [retracted]... up, run.1231 (Free)
D, [2016-10-11T06:15:07.562673 #3] DEBUG -- :    (0.8ms)  SELECT pg_try_advisory_lock(6976026441189414000);
D, [2016-10-11T06:15:07.572811 #3] DEBUG -- :   ActiveRecord::SchemaMigration Load (1.0ms)  SELECT "schema_migrations".* FROM "schema_migrations"
I, [2016-10-11T06:15:07.577534 #3]  INFO -- : Migrating to CreateComments (20160928024026)
D, [2016-10-11T06:15:07.579481 #3] DEBUG -- :    (0.7ms)  BEGIN
== 20160928024026 CreateComments: migrating ===================================
-- create_table(:comments)
D, [2016-10-11T06:15:07.594892 #3] DEBUG -- :    (13.9ms)  CREATE TABLE "comments" ("id" serial primary key, "user_id" integer, "body" text, "blog_post_id" integer, "created_at" timestamp NOT NULL, "updated_at" timestamp NOT NULL, CONSTRAINT "fk_rails_03de2dc08c"
FOREIGN KEY ("user_id")
  REFERENCES "users" ("id")
, CONSTRAINT "fk_rails_29c545254e"
FOREIGN KEY ("blog_post_id")
  REFERENCES "blog_posts" ("id")
)
D, [2016-10-11T06:15:07.595917 #3] DEBUG -- :    (0.7ms)  ROLLBACK
D, [2016-10-11T06:15:07.597131 #3] DEBUG -- :    (0.9ms)  SELECT pg_advisory_unlock(6976026441189414000)
rails aborted!
StandardError: An error has occurred, this and all later migrations canceled:

PG::UndefinedTable: ERROR:  relation "users" does not exist
: CREATE TABLE "comments" ("id" serial primary key, "user_id" integer, "body" text, "blog_post_id" integer, "created_at" timestamp NOT NULL, "updated_at" timestamp NOT NULL, CONSTRAINT "fk_rails_03de2dc08c"
FOREIGN KEY ("user_id")
  REFERENCES "users" ("id")
, CONSTRAINT "fk_rails_29c545254e"
FOREIGN KEY ("blog_post_id")
  REFERENCES "blog_posts" ("id")
)
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:98:in `async_exec'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:98:in `block in execute'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract_adapter.rb:566:in `block in log'
/app/vendor/bundle/ruby/2.2.0/gems/activesupport-5.0.0.1/lib/active_support/notifications/instrumenter.rb:21:in `instrument'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract_adapter.rb:560:in `log'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:97:in `execute'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/schema_statements.rb:283:in `create_table'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:845:in `block in method_missing'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:814:in `block in say_with_time'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:814:in `say_with_time'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:834:in `method_missing'
/app/db/migrate/20160928024026_create_comments.rb:3:in `change'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:788:in `exec_migration'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:772:in `block (2 levels) in migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:771:in `block in migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:398:in `with_connection'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:770:in `migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:950:in `migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1211:in `block in execute_migration_in_transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1279:in `block in ddl_transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/database_statements.rb:232:in `block in transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/transaction.rb:189:in `within_new_transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/database_statements.rb:232:in `transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/transactions.rb:211:in `transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1279:in `ddl_transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1210:in `execute_migration_in_transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1183:in `block in migrate_without_lock'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1182:in `each'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1182:in `migrate_without_lock'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1131:in `block in migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1298:in `with_advisory_lock'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1131:in `migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1005:in `up'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:983:in `migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/tasks/database_tasks.rb:161:in `migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/railties/databases.rake:58:in `block (2 levels) in <top (required)>'
/app/vendor/bundle/ruby/2.2.0/gems/railties-5.0.0.1/lib/rails/commands/rake_proxy.rb:13:in `block in run_rake_task'
/app/vendor/bundle/ruby/2.2.0/gems/railties-5.0.0.1/lib/rails/commands/rake_proxy.rb:10:in `run_rake_task'
/app/vendor/bundle/ruby/2.2.0/gems/railties-5.0.0.1/lib/rails/commands/commands_tasks.rb:51:in `run_command!'
/app/vendor/bundle/ruby/2.2.0/gems/railties-5.0.0.1/lib/rails/commands.rb:18:in `<top (required)>'
/app/bin/rails:9:in `require'
/app/bin/rails:9:in `<main>'
ActiveRecord::StatementInvalid: PG::UndefinedTable: ERROR:  relation "users" does not exist
: CREATE TABLE "comments" ("id" serial primary key, "user_id" integer, "body" text, "blog_post_id" integer, "created_at" timestamp NOT NULL, "updated_at" timestamp NOT NULL, CONSTRAINT "fk_rails_03de2dc08c"
FOREIGN KEY ("user_id")
  REFERENCES "users" ("id")
, CONSTRAINT "fk_rails_29c545254e"
FOREIGN KEY ("blog_post_id")
  REFERENCES "blog_posts" ("id")
)
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:98:in `async_exec'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:98:in `block in execute'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract_adapter.rb:566:in `block in log'
/app/vendor/bundle/ruby/2.2.0/gems/activesupport-5.0.0.1/lib/active_support/notifications/instrumenter.rb:21:in `instrument'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract_adapter.rb:560:in `log'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:97:in `execute'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/schema_statements.rb:283:in `create_table'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:845:in `block in method_missing'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:814:in `block in say_with_time'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:814:in `say_with_time'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:834:in `method_missing'
/app/db/migrate/20160928024026_create_comments.rb:3:in `change'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:788:in `exec_migration'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:772:in `block (2 levels) in migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:771:in `block in migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:398:in `with_connection'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:770:in `migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:950:in `migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1211:in `block in execute_migration_in_transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1279:in `block in ddl_transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/database_statements.rb:232:in `block in transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/transaction.rb:189:in `within_new_transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/database_statements.rb:232:in `transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/transactions.rb:211:in `transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1279:in `ddl_transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1210:in `execute_migration_in_transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1183:in `block in migrate_without_lock'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1182:in `each'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1182:in `migrate_without_lock'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1131:in `block in migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1298:in `with_advisory_lock'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1131:in `migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1005:in `up'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:983:in `migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/tasks/database_tasks.rb:161:in `migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/railties/databases.rake:58:in `block (2 levels) in <top (required)>'
/app/vendor/bundle/ruby/2.2.0/gems/railties-5.0.0.1/lib/rails/commands/rake_proxy.rb:13:in `block in run_rake_task'
/app/vendor/bundle/ruby/2.2.0/gems/railties-5.0.0.1/lib/rails/commands/rake_proxy.rb:10:in `run_rake_task'
/app/vendor/bundle/ruby/2.2.0/gems/railties-5.0.0.1/lib/rails/commands/commands_tasks.rb:51:in `run_command!'
/app/vendor/bundle/ruby/2.2.0/gems/railties-5.0.0.1/lib/rails/commands.rb:18:in `<top (required)>'
/app/bin/rails:9:in `require'
/app/bin/rails:9:in `<main>'
PG::UndefinedTable: ERROR:  relation "users" does not exist
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:98:in `async_exec'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:98:in `block in execute'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract_adapter.rb:566:in `block in log'
/app/vendor/bundle/ruby/2.2.0/gems/activesupport-5.0.0.1/lib/active_support/notifications/instrumenter.rb:21:in `instrument'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract_adapter.rb:560:in `log'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/postgresql/database_statements.rb:97:in `execute'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/schema_statements.rb:283:in `create_table'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:845:in `block in method_missing'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:814:in `block in say_with_time'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:814:in `say_with_time'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:834:in `method_missing'
/app/db/migrate/20160928024026_create_comments.rb:3:in `change'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:788:in `exec_migration'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:772:in `block (2 levels) in migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:771:in `block in migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:398:in `with_connection'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:770:in `migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:950:in `migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1211:in `block in execute_migration_in_transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1279:in `block in ddl_transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/database_statements.rb:232:in `block in transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/transaction.rb:189:in `within_new_transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/database_statements.rb:232:in `transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/transactions.rb:211:in `transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1279:in `ddl_transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1210:in `execute_migration_in_transaction'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1183:in `block in migrate_without_lock'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1182:in `each'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1182:in `migrate_without_lock'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1131:in `block in migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1298:in `with_advisory_lock'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1131:in `migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:1005:in `up'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/migration.rb:983:in `migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/tasks/database_tasks.rb:161:in `migrate'
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-5.0.0.1/lib/active_record/railties/databases.rake:58:in `block (2 levels) in <top (required)>'
/app/vendor/bundle/ruby/2.2.0/gems/railties-5.0.0.1/lib/rails/commands/rake_proxy.rb:13:in `block in run_rake_task'
/app/vendor/bundle/ruby/2.2.0/gems/railties-5.0.0.1/lib/rails/commands/rake_proxy.rb:10:in `run_rake_task'
/app/vendor/bundle/ruby/2.2.0/gems/railties-5.0.0.1/lib/rails/commands/commands_tasks.rb:51:in `run_command!'
/app/vendor/bundle/ruby/2.2.0/gems/railties-5.0.0.1/lib/rails/commands.rb:18:in `<top (required)>'
/app/bin/rails:9:in `require'
/app/bin/rails:9:in `<main>'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)

我已经尝试了一些其他的解决方案，但到目前为止都没有奏效。谢谢!

Answer 1

看起来你在 users 之前创建了 comments 表，同时在 comments 中使用了 user_id 外键table 它失败了，因为还没有这样的表。

确保您的迁移顺序正确(用户，然后是评论)。

通常，您应该始终首先创建表/列，只有在创建和迁移它们之后，才引用它们。