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rails activerecord属性=

activerecord ruby ruby-on-rails

1

vinhboy · 技术社区 · 16 年前

我正在做:

@person.attributes = params[:person]

有人能告诉我为什么做attributes=会导致一堆sql显示在我的日志中吗?

我看到一些精选的甚至是更新的。

我发誓我不是在做“保存”——所以我不知道为什么设置属性会触发查询。

是否有我丢失的前/后过滤器?

谢谢。

1 回复 | 直到 16 年前

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Ryan Bigg Andrés Bonilla 16 年前

在标准模型上设置属性不会导致 SELECT 或 UPDATE 据我所知打电话来。当我与 脚本/控制台 会议:

>> f = Forum.first

==> ./log/development.log <==
  SQL (0.1ms)   SET SQL_AUTO_IS_NULL=0
  Forum Load (0.4ms)   SELECT * FROM `forums` ORDER BY title asc LIMIT 1
  Forum Columns (12.6ms)   SHOW FIELDS FROM `forums`
=> #<Forum id: 1, title: "Welcome to rBoard!", description: "This is an example forum for Rboard.", is_visible_to_id: nil, topics_created_by_id: nil, position: 1, parent_id: nil, last_post_id: 1, last_post_forum_id: nil, topics_count: 1, posts_count: 4, category_id: nil, active: true, open: true>
>> f.attributes
=> {"position"=>1, "is_visible_to_id"=>nil, "open"=>true, "topics_count"=>1, "title"=>"Welcome to rBoard!", "last_post_forum_id"=>nil, "posts_count"=>4, "id"=>1, "category_id"=>nil, "parent_id"=>nil, "topics_created_by_id"=>nil, "last_post_id"=>1, "description"=>"This is an example forum for Rboard.", "active"=>true}
>> f.attributes = _
=> {"position"=>1, "is_visible_to_id"=>nil, "open"=>true, "topics_count"=>1, "title"=>"Welcome to rBoard!", "last_post_forum_id"=>nil, "posts_count"=>4, "id"=>1, "category_id"=>nil, "parent_id"=>nil, "topics_created_by_id"=>nil, "last_post_id"=>1, "description"=>"This is an example forum for Rboard.", "active"=>true}

在这里可以看到,只有两个sql查询被执行,一个用来获取 Forum 记录并另一个查找 forums 表。

直到我保存它,它才执行一些查询:

>> f.attributes
=> {"position"=>1, "is_visible_to_id"=>nil, "open"=>true, "topics_count"=>1, "title"=>"Welcome to rBoard!", "last_post_forum_id"=>nil, "posts_count"=>4, "id"=>1, "category_id"=>nil, "parent_id"=>nil, "topics_created_by_id"=>nil, "last_post_id"=>1, "description"=>"This is an example forum for Rboard.", "active"=>true}
>> attr = _
=> {"position"=>1, "is_visible_to_id"=>nil, "open"=>true, "topics_count"=>1, "title"=>"Welcome to rBoard!", "last_post_forum_id"=>nil, "posts_count"=>4, "id"=>1, "category_id"=>nil, "parent_id"=>nil, "topics_created_by_id"=>nil, "last_post_id"=>1, "description"=>"This is an example forum for Rboard.", "active"=>true}
>> attr["position"] = 2
=> 2
>> f.save
  SQL (0.2ms)   BEGIN
=> true
>>   SQL (0.2ms)   COMMIT
f.attributes = attr
=> {"position"=>2, "is_visible_to_id"=>nil, "open"=>true, "topics_count"=>1, "title"=>"Welcome to rBoard!", "last_post_forum_id"=>nil, "posts_count"=>4, "id"=>1, "category_id"=>nil, "parent_id"=>nil, "topics_created_by_id"=>nil, "last_post_id"=>1, "description"=>"This is an example forum for Rboard.", "active"=>true}
>> WARNING: Can't mass-assign these protected attributes: id
f.save
  SQL (0.2ms)   BEGIN
  Forum Update (20.3ms)   UPDATE `forums` SET `position` = 2 WHERE `id` = 1
  SQL (27.2ms)   COMMIT
=> true