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rake db：migrateで問題が発生しています。この問題は、scaffoldを使用してモデルを作成し、db：migrateを実行してから、scaffolddPostsを使用してモデルを削除したときに始まりました。

ここで、scaffold gを使用してモデルを再度作成し、db：migrateを実行しました。ユーザーテーブルがすでに存在していたため、エラーが発生しました。どうすればこれを修正できますか？

murtaza@murtaza-dev:~/workspace/rails/base$ rake db:migrate
==  CreatePosts: migrating ====================================================
-- create_table(:posts) rake aborted! An error has occurred, this and all later migrations canceled:

SQLite3::SQLException: table "posts" already exists: CREATE TABLE "posts" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, "name" varchar(255), "content" text, "created_at" datetime NOT NULL, "updated_at" datetime NOT NULL) 

Tasks: TOP => db:migrate (See full trace by running task with --trace) murtaza@murtaza-dev:~/workspace/rails/base$ rake db:migrate --trace
** Invoke db:migrate (first_time)
** Invoke environment (first_time)
** Execute environment
** Invoke db:load_config (first_time)
** Invoke rails_env (first_time)
** Execute rails_env
** Execute db:load_config
** Execute db:migrate
==  CreatePosts: migrating ====================================================
-- create_table(:posts) rake aborted! An error has occurred, this and all later migrations canceled:

SQLite3::SQLException: table "posts" already exists: CREATE TABLE "posts" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, "name" varchar(255), "content" text, "created_at" datetime NOT NULL, "updated_at" datetime NOT NULL)  /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/sqlite3-1.3.6/lib/sqlite3/database.rb:91:in `initialize' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/sqlite3-1.3.6/lib/sqlite3/database.rb:91:in `new' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/sqlite3-1.3.6/lib/sqlite3/database.rb:91:in `prepare' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/sqlite3-1.3.6/lib/sqlite3/database.rb:134:in `execute' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/connection_adapters/sqlite_adapter.rb:278:in `block in execute' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract_adapter.rb:280:in `block in log' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.6/lib/active_support/notifications/instrumenter.rb:20:in `instrument' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract_adapter.rb:275:in `log' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/connection_adapters/sqlite_adapter.rb:278:in `execute' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract/schema_statements.rb:170:in `create_table' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/migration.rb:466:in `block in method_missing' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/migration.rb:438:in `block in say_with_time' /home/murtaza/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/benchmark.rb:280:in `measure' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/migration.rb:438:in `say_with_time' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/migration.rb:458:in `method_missing' /home/murtaza/workspace/rails/base/db/migrate/20120802061742_create_posts.rb:3:in `change' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/migration.rb:407:in `block (2 levels) in migrate' /home/murtaza/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/benchmark.rb:280:in `measure' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/migration.rb:407:in `block in migrate' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract/connection_pool.rb:123:in `with_connection' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/migration.rb:389:in `migrate' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/migration.rb:528:in `migrate' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/migration.rb:720:in `block (2 levels) in migrate' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/migration.rb:775:in `call' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/migration.rb:775:in `block in ddl_transaction' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract/database_statements.rb:192:in `transaction' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/transactions.rb:208:in `transaction' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/migration.rb:775:in `ddl_transaction' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/migration.rb:719:in `block in migrate' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/migration.rb:700:in `each' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/migration.rb:700:in `migrate' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/migration.rb:570:in `up' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/migration.rb:551:in `migrate' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.6/lib/active_record/railties/databases.rake:153:in `block (2 levels) in <top (required)>' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `call' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `block in execute' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `each' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `execute' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain' /home/murtaza/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/lib/rake/task.rb:144:in `invoke' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/lib/rake/application.rb:116:in `invoke_task' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block (2 levels) in top_level' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `each' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block in top_level' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/lib/rake/application.rb:88:in `top_level' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/lib/rake/application.rb:66:in `block in run' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/gems/rake-0.9.2.2/bin/rake:33:in `<top (required)>' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/bin/rake:23:in `load' /home/murtaza/.rvm/gems/ruby-1.9.3-p194/bin/rake:23:in `<main>' Tasks: TOP => db:migrate
4

2 に答える 2

6

試す

rake db:drop && rake db:create && rake db:migrate && rake db:schema:dump && rake db:test:prepare

また

rake db:schema:load

参照： RubyonRailsデータベースをパージまたは再作成する

複数の移行により、ユーザーテーブルが複数回作成されています。各移行を手動で調べて、テーブルの作成クエリを削除できます。

于 2012-08-03T05:48:50.163 に答える
1

AFAIKscaffold dは、テーブルを削除するための移行を生成しません。自分で行う必要があります。手動で移行を追加して、テーブルを削除できます。

def up
    drop_table :posts
end
def down
    raise ActiveRecord::IrreversibleMigration
end

そしてrake db:migrate、それが再作成を試みる新しい移行の前に来ることを確認してくださいposts。sqlite3または、コマンドラインツールを使用してデータベースを開きdrop table posts;、テーブルを手動で削除するように指示することもできます。

于 2012-08-03T05:54:07.050 に答える