ecto删除预加载 [英] Ecto remove preload
本文介绍了ecto删除预加载的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
有什么方法可以做相反的预加载吗?
%Post {
评论:[]
}
个帖子= Repo.all(Post)|> Repo.unload(:comments)
%Post {
评论:#Ecto.Association.NotLoaded< association:评论未加载> ;,
}
解决方案
Ecto.Association.NotLoaded
很老简单的结构,因此您自己可以相对容易地实现 unpreload
:
defmodule Unpreloader做
def忘记(结构,字段,基数\\:one)做
%{struct |
字段=> %Ecto.Association.NotLoaded {
__field__:字段,
__owner__:struct .__ struct__,
__cardinality__:基数
}
}
结尾
end
以后使用它:
< pre class = lang-rb prettyprint-override>
Unpreloader.forget(%Post {....},:comments)
Is there any way to do the inverse to preload?
%Post{
comments: []
}
posts = Repo.all(Post) |> Repo.unload(:comments)
%Post{
comments: #Ecto.Association.NotLoaded<association :comments is not loaded>,
}
解决方案
Ecto.Association.NotLoaded
is a plain old simple struct, so you might relatively easy implement this unpreload
youself:
defmodule Unpreloader do
def forget(struct, field, cardinality \\ :one) do
%{struct |
field => %Ecto.Association.NotLoaded{
__field__: field,
__owner__: struct.__struct__,
__cardinality__: cardinality
}
}
end
end
And use it later as:
Unpreloader.forget(%Post{....}, :comments)
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