Phoenix和Ecto和SELECTs [英] Phoenix and Ecto and SELECTs

问题描述

我在Phoenix的Ecto模型中建立了一个关联.一个组织有许多OrganizationMembers.在OrganizationMember控制器的Edit方法中，我试图创建一个SELECT元素，该元素将保留所有可供选择的组织.在 edit 定义中，我有以下两行:

I have an association set up in Ecto models in Phoenix. An Organization has many OrganizationMembers. In the OrganizationMember controller's Edit method, I'm trying to create a SELECT element that will hold all of the Organizations to choose from. In the edit definitiion, I've got the following two lines:

# organizations = Enum.to_list(from(o in Organization, order_by: o.name, select: [o.name, o.id]))
organizations = from(o in Organization, order_by: o.name, select: {o.name, o.id})

这是我在模板中显示选择内容的行:

This is my line in the template to show the select:

<%= select f, :organization_id, @organizations, prompt: "Choose your organization" %>

如果我保留第一行的注释，则会在选择的模板上收到此错误:

If I keep the first line commented, I get this error on the template select:

#Ecto.Query协议未实现Enumerable

protocol Enumerable not implemented for #Ecto.Query

如果我使用第一行并注释第二行，则会在控制器中收到此错误:

If I use the first line and comment the second one, I get this error in the controller:

#Ecto.Query协议未实现Enumerable

protocol Enumerable not implemented for #Ecto.Query

如何获取选择以正确显示选择下拉列表和值?顺便说一句，organization_id来自此:

How do I get the select to properly show the select dropdown and the values? BTW the organization_id comes from this:

organization_member = Repo.get!(OrganizationMember, id) |> Repo.preload(:organization)    
organization_id = organization_member.organization.id

推荐答案

如错误消息所述，%Ecto.Query{}不能枚举.如果要带来查询结果，则必须调用存储库并为其查询:

As the error messages say, an %Ecto.Query{} is not an Enumerable. If you want to bring the query results, you must call the repository and give it the query:

Repo.all from(o in Organization, order_by: o.name, select: {o.name, o.id})

PS:注意，我将select返回的值更改为元组，因为这正是select所需的形式.

PS: Note I changed the valued returned by select into a tuple because that's what the form select needs.

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