def self.up
create_table :test_drafts do |t|
t.string :title, :limit => 255, :null => false
t.text :description
t.integer :user_id, :null => false
t.integer :test_id, :null => false
t.timestamps
end
add_foreign_key(:test_drafts,:user_id,:users,:cascade)
add_foreign_key(:test_drafts,:test_id,:tests,:cascade)
end
def self.down
drop_foreign_key(:test_drafts,:user_id)
drop_foreign_key(:test_drafts,:test_id)
drop_table(:test_drafts)
end
我们真的需要删除外键之前下降的表? 我可以直接删除表而不丢弃外键吗?