0

私はテーブルを持っています、Personsと言います

person = Person.find(:first)
person.delete

私は得る

NoMethodError: undefined method `to_sym' for nil:NilClass
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activesupport-3.1.1/lib/active_support/whiny_nil.rb:48:in `method_missing'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/base.rb:1403:in `block in expand_hash_conditions_for_aggregates'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/base.rb:1402:in `each'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/base.rb:1402:in `expand_hash_conditions_for_aggregates'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/relation/query_methods.rb:261:in `build_where'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/relation/query_methods.rb:124:in `where'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/relation.rb:380:in `delete'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/base.rb:442:in `delete'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/persistence.rb:72:in `delete'
        from (irb):60
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/railties-3.1.1/lib/rails/commands/console.rb:45:in `start'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/railties-3.1.1/lib/rails/commands/console.rb:8:in `start'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/railties-3.1.1/lib/rails/commands.rb:40:in `<top (required)>'
        from script/rails:6:in `require'
        from script/rails:6:in `<main>'

私が行った場合

person.destroy

私は得る

  SQL (0.2ms)  BEGIN
Could not log "sql.active_record" event. NoMethodError: undefined method `name' for nil:NilClass
Mysql::Error: Unknown column 'persons.' in 'where clause': DELETE FROM `persons` WHERE `persons`.`` = ?
   (0.1ms)  ROLLBACK
ActiveRecord::StatementInvalid: Mysql::Error: Unknown column 'persons.' in 'where clause': DELETE FROM `persons` WHERE `persons`.`` = ?
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/mysql_adapter.rb:883:in `prepare'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/mysql_adapter.rb:883:in `exec_stmt'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/mysql_adapter.rb:490:in `block in exec_delete'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/abstract_adapter.rb:244:in `block in log'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activesupport-3.1.1/lib/active_support/notifications/instrumenter.rb:21:in `instrument'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/abstract_adapter.rb:239:in `log'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/mysql_adapter.rb:489:in `exec_delete'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/abstract/database_statements.rb:101:in `delete'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/abstract/query_cache.rb:14:in `delete'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/relation.rb:351:in `delete_all'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/persistence.rb:94:in `destroy'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/locking/optimistic.rb:119:in `destroy'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/callbacks.rb:254:in `block in destroy'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activesupport-3.1.1/lib/active_support/callbacks.rb:390:in `_run_destroy_callbacks'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activesupport-3.1.1/lib/active_support/callbacks.rb:81:in `run_callbacks'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/callbacks.rb:254:in `destroy'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/transactions.rb:236:in `block in destroy'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/transactions.rb:295:in `block in with_transaction_returning_status'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/abstract/database_statements.rb:192:in `transaction'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/transactions.rb:208:in `transaction'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/transactions.rb:293:in `with_transaction_returning_status'
        from .rvm/gems/ruby-1.9.2-p320@rails-3.1.1/gems/activerecord-3.1.1/lib/active_record/transactions.rb:236:in `destroy'
        from (irb):61

ただし、SQLの削除ステートメントを記述すれば、MySQLコンソールからレコードを削除できます。何が起こっているのか考えてみませんか？

その他の情報： Personテーブルにはid列がありますが、データベースの主キーはidと他のいくつかの列を使用する複合キーです。人物モデルは他の誰かによって作成され、いくつかのメソッドが作成されていますが、deleteまたはdestroyという名前のメソッドは明示的に作成されていません。

4

1 に答える 1

2 
@person = Person.first
@person.destroy

非標準の主キーを使用した場合は、最初に設定する必要があります。

Person.primary_key = 'person_id'
@person = Person.first
@person.destroy

他のすべてが失敗した場合...これを入力するのは気分が悪いです：

Person.connection.execute("delete from persons where id = 1 and state_id = 2 and project_id = 5")

現在および将来の悪夢を救うために、データベースを再構築して、レールの標準的なデータ保存方法に従う必要があります。Person テーブルには、主キーである一意の ID 列を持つ一意の人物のみを含める必要があります。新しい project_assignments テーブル/モデルを作成して、独自の一意の ID と、state_id、project_id、および person_id を持つ割り当てを処理する必要があります。Person に属するデータはそのテーブルに存在する必要があり、割り当てデータは project_assignments などに移動する必要があります。

于 2012-10-05T18:29:26.173 に答える