新手问题 ActiveRecord 优化问题
Tagging 有一个 [:tag_id, :taggable_id, :taggable_type] 的 unique 制约，下面的代码有什么办法可以优化一下么？
def merge_taggings(remained_tag_id, delete_tag_ids)
Tagging.where(tag_id: delete_tag_ids).each do |tagging|
if Tagging.exists?(tagging.taggable_id, tagging.taggable_type, tag_id: remained_tag_id)
tagging.delete
else
tagging.update(tag_id: remained_tag_id)
end
end
end
可以加一个字段，比如 should_delete
然后对Tagging.where(tag_id: delete_tag_ids)做批量更新
冲突时update should_delete = 1，然后再Tagging.where(should_delete:1).delete
