blocks|key|1948318|text|关系对象可以转换为数组。这就否定了以后可以对它们使用任何ActiveRecord方法，但我不需要这样做。我这样做了：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1948319|name_relation+=+first_name_relation+%2B+last_name_relation|code-block|syntax|javascript|1948320|Ruby+1.9，rails+3.2|1948321|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Relation objects can be converted to arrays. This negates being able to use any ActiveRecord methods on them afterwards, but I didn't need to. I did this:

<pre><code>name_relation = first_name_relation + last_name_relation
</code></pre>

Ruby 1.9, rails 3.2

blocks|key|1734918|text|实际上，merge并不像OR那样工作。这是简单的交集(AND)|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1734919|为了将ActiveRecord::Relation对象合并为一个对象，我努力解决了这个问题，但我没有找到任何适合我的解决方案。|1734920|我没有寻找从这两个集合创建并集的正确方法，而是专注于集合代数。您可以使用De+Morgan's+law以不同的方式完成此操作|1734921|ActiveRecord提供了merge方法(和)，您也可以使用not方法或none_of+(NOT)。|1734922|search.where.none_of(search.where.not(id:+ids_to_exclude).merge(search.where.not("title+ILIKE+?",+"%25#{query}%25")))|code-block|syntax|javascript|1734923|这里有(A+U+B)‘=+A’%5E+B‘|1734924|更新:上面的解决方案适用于更复杂的情况。在你的例子中，像这样的smth就足够了：|1734925|User.where('first_name+LIKE+?+OR+last_name+LIKE+?',+'Tobias',+'Fünke')|1734926|entityMap|0|LINK|mutability|MUTABLE|url|http://en.wikipedia.org/wiki/De_Morgan%2527s_laws^0|4|5|C|2|R|3|0|0|10|F|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@$9|15|A|16|B|C]|$9|17|A|18|B|C]|$9|19|A|1A|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|1B|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|1C|8|@]|D|@$9|1D|A|1E|1|1F]]|E|$]]|$1|J|3|K|5|6|7|1G|8|@]|D|@]|E|$]]|$1|L|3|M|5|N|7|1H|8|@]|D|@]|E|$O|P]]|$1|Q|3|R|5|6|7|1I|8|@]|D|@]|E|$]]|$1|S|3|T|5|6|7|1J|8|@]|D|@]|E|$]]|$1|U|3|V|5|N|7|1K|8|@]|D|@]|E|$O|P]]|$1|W|3|-4|5|6|7|1L|8|@]|D|@]|E|$]]]|X|$Y|$5|Z|10|11|E|$12|13]]]]

<code>merge</code> actually doesn't work like <code>OR</code>. It's simply intersection (<code>AND</code>) 

I struggled with this problem to combine to ActiveRecord::Relation objects into one and I didn't found any working solution for me. 

Instead of searching for right method creating an union from these two sets, I focused on algebra of sets. You can do it in different way using <a href="http://en.wikipedia.org/wiki/De_Morgan%27s_laws">De Morgan's law</a>

ActiveRecord provides merge method (AND) and also you can use not method or none_of (NOT). 

<pre><code>search.where.none_of(search.where.not(id: ids_to_exclude).merge(search.where.not("title ILIKE ?", "%#{query}%")))
</code></pre>

You have here (A u B)' = A' ^ B'

UPDATE:
The solution above is good for more complex cases. 
In your case smth like that will be enough:

<pre><code>User.where('first_name LIKE ? OR last_name LIKE ?', 'Tobias', 'Fünke')
</code></pre>

blocks|key|1948446|text|有一个名为active_record_union的宝石可能就是你要找的。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1948447|它的示例用法如下：|1948448|current_user.posts.union(Post.published)
current_user.posts.union(Post.published).where(id:+[6,+7])
current_user.posts.union("published_at+<+?",+Time.now)
user_1.posts.union(user_2.posts).union(Post.published)
user_1.posts.union_all(user_2.posts)|code-block|syntax|javascript|1948449|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/brianhempel/active_record_union^0|5|J|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|6|7|W|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|X|8|@]|9|@]|C|$I|J]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]]]

There is a gem called <a href="https://github.com/brianhempel/active_record_union" rel="noreferrer">active_record_union</a>
that might be what you are looking for. 

It's example usages is the following:

<pre><code>current_user.posts.union(Post.published)
current_user.posts.union(Post.published).where(id: [6, 7])
current_user.posts.union("published_at &lt; ?", Time.now)
user_1.posts.union(user_2.posts).union(Post.published)
user_1.posts.union_all(user_2.posts)
</code></pre>

blocks|key|1948500|text|如果您有一个activerecord关系数组，并且希望将它们全部合并，您可以这样做|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1948501|array.inject(:merge)|code-block|syntax|javascript|1948502|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

If you have an array of activerecord relations and want to merge them all, you can do 

<pre><code>array.inject(:merge)
</code></pre>

blocks|key|1948516|text|暴力破解它：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1948517|first_name_relation+=+User.where(:first_name+=>+'Tobias')+#+ActiveRecord::Relation
last_name_relation++=+User.where(:last_name++=>+'Fünke')+#+ActiveRecord::Relation

all_name_relations+=+User.none
first_name_relation.each+do+%7Car%7C
++all_name_relations.new(ar)
end
last_name_relation.each+do+%7Car%7C
++all_name_relations.new(ar)
end|code-block|syntax|javascript|1948518|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Brute force it:

<pre><code>first_name_relation = User.where(:first_name =&gt; 'Tobias') # ActiveRecord::Relation
last_name_relation = User.where(:last_name =&gt; 'Fünke') # ActiveRecord::Relation

all_name_relations = User.none
first_name_relation.each do |ar|
 all_name_relations.new(ar)
end
last_name_relation.each do |ar|
 all_name_relations.new(ar)
end
</code></pre>

blocks|key|1948547|text|这就是我如何“处理”它，如果你使用pluck来获取每个记录的标识符，将数组连接在一起，然后最后对这些连接的if执行查询：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1948548|++transaction_ids+=+@club.type_a_trans.pluck(:id)+%2B+@club.type_b_transactions.pluck(:id)+%2B+@club.type_c_transactions.pluck(:id)
++@transactions+=+Transaction.where(id:+transaction_ids).limit(100)|code-block|syntax|javascript|1948549|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This is how I've "handled" it if you use pluck to get an identifier for each of the records, join the arrays together and then finally do a query for those joined ids:

<pre><code> transaction_ids = @club.type_a_trans.pluck(:id) + @club.type_b_transactions.pluck(:id) + @club.type_c_transactions.pluck(:id)
 @transactions = Transaction.where(id: transaction_ids).limit(100)
</code></pre>

blocks|key|1948620|text|希望这对外面的人有用--您可以进行第二个查询，根据id查找匹配项：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1948621|ids+=+last_name_relation.ids+%2B+first_name_relation.ids
User.where(id:+ids)|code-block|syntax|javascript|1948622|我意识到对于3个数据库请求，这可能不是最有效的，但它完成了工作，并且很容易理解。|1948623|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Hopefully this is useful to someone out there -- you can make a second query to find the matches by id:
<pre><code>ids = last_name_relation.ids + first_name_relation.ids
User.where(id: ids)
</code></pre>
I realize this may not be the most efficient with 3 database requests, but it gets the job done and is simple to understand.

Suppose I have the following two objects:

<pre><code>first_name_relation = User.where(:first_name =&gt; 'Tobias') # ActiveRecord::Relation
last_name_relation = User.where(:last_name =&gt; 'Fünke') # ActiveRecord::Relation
</code></pre>

is it possible to combine the two relations to produce one <code>ActiveRecord::Relation</code> object containing both conditions?

Note: I'm aware that I can chain the wheres to get this behavior, what I'm really interested in is the case where I have two separate <code>ActiveRecord::Relation</code> objects.

Combine two ActiveRecord::Relation objects

数据库

假设我有以下两个对象：first_name_relation = User.where(:first_name => 'Tobias') # ActiveRecord::Relationlast_name_relation  = User.where(:last_name  => 'Fünke') # ActiveRe...

问组合两个ActiveRecord::Relation对象
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问组合两个ActiveRecord::Relation对象EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问组合两个ActiveRecord::Relation对象
EN