使用Array使用Meteor js在集合中查找文档 [英] Using array to find documents in a collection using Meteor js

问题描述

帮助程序方法

  GetSchoolId：function（）{
 var moduleIdArray = []; 
 var myslug = FlowRouter.getParam（'myslug'）; 
 var mySchoolId = SchoolDb.findOne（{slug：myslug}）; 
 if（mySchoolId）{
 ModuleSchool.find（{}，{schoolId：mySchoolId._id}）.forEach（function（modulesSelected）{
 moduleIdArray.push（modulesSelected.moduleId）; 
}）; 
 if（typeof moduleIdArray ==='object'&& moduleIdArray instanceof Array）{
 console.log（moduleIdArray）; 
 moduleIdArray.forEach（function（moduleIds）{
 return Modules.find（{}，{_id：moduleIds}）。fetch（）; 
}）; 
 
 
 $ b  

模板代码：

  {{＃each GetSchoolId}} 
< p> {{GetSchoolId.modulename}}< / p> 
 {{/ each}} 
< / p> 
 {{/每个}} 
  

我知道Meteor Profs，它是一寸一个冰山，几秒钟内就会被丢弃。我有3个集合，一个是学校记录（ SchoolDb ），第二个是模块（Modules），第三个是关系表（ ModuleSchool ）。模块分配给学校。

从上面的代码中，我可以从（ SchoolDb ）使用传递给我用来从关系表（ SchoolDb ）中获取 schoolId （ ModuleSchool ）返回分配给相关学校的模块。我能够获取模块ID并将它们转换为数组，我现在要做的就是使用从 ModuleSchool 中获取的ID数组返回模块名称因为只有 _ids 存储在关系表中。

上面的代码只能达到级别将_ids转换为数组，当我试图在模板上打印什么都没有显示。我有什么不对的？

解决方案

要找到一个字段对应至少一个数组的元素，您可以使用 $ in ：

  Template.my_template.helpers（{
模块（）{
 var myslug = FlowRouter.getParam（'myslug'）; 
 var mySchoolDoc = SchoolDb.findOne（{slug：myslug}）; 
 var arrayModuleSchool = ModuleSchool.find {schoolId：mySchoolDoc._id}）; 
 //将文档数组转换为仅包含ids的数组
 var arrayModuleIds = []; 
 arrayModuleSchool.forEach（function（moduleSchool）） {
 arrayModuleIds.push（moduleSchool.moduleId）; 
}）; 
 return Modules.find（{_ id：{$ in：arrayModuleIds}}。fetch（）; 
} 
}）; 
  

然后简单地使用 {{each}} 标签。

 < template name =my_template> 
 {{#each module in modules}} 
< p> {{module.modulename}}< / p> 
 {{/ each}} 
< / template>但是，如果每个模块只连接到一所学校，我建议你的问题更简单的解决方案，你不必在学校和模块之间创建一个集合。
 
 
 
 您只需要创建两个集合： Schools 和 Modules 并添加到模块文档a  schoolId 字段。
 
 
 
然后你的代码看起来像这样： 
 
 
  Template.my_template.helpers（{ b $ b modules（）{
 var myslug = FlowRouter.getParam（'myslug'）; 
 var mySchoolDoc = Schools.findOne（{slug：myslug}）; 
返回Modules.find {schoolId：mySchoolDoc._id}）。fetch（）; 
} 
}）; 
  
 
Helper method
  GetSchoolId: function () {
            var moduleIdArray=[];
            var myslug = FlowRouter.getParam('myslug');
            var mySchoolId = SchoolDb.findOne({slug: myslug});
            if (mySchoolId) {
                ModuleSchool.find({}, {schoolId: mySchoolId._id}).forEach(function (modulesSelected) {
                    moduleIdArray.push(modulesSelected.moduleId);
                });
                if (typeof moduleIdArray === 'object' && moduleIdArray instanceof Array) {
                    console.log(moduleIdArray);
                    moduleIdArray.forEach(function (moduleIds) {
                        return Modules.find({}, {_id: moduleIds}).fetch();
                    });
                }
            }
        }
Template code:
{{#each GetSchoolId }} 
    <p>{{GetSchoolId.modulename}} </p>
    {{/each}}
    </p>
{{/each}}
I know to Meteor Profs, it is a inch of an iceberg, in seconds it will be trashed. I have 3 collections, one for school record (SchoolDb), second for for module (Modules), and the third, a relationship table (ModuleSchool). modules are assigned to schools.


From the code above, I am able to get the school _id from (SchoolDb) using the slug passed to the route which I used to fetch the schoolId from the relationship table (SchoolDb) and the (ModuleSchool) to return modules assigned to a the school in question. I was able to fetch the module Ids and converted them into arrays, what I now want to do is using the array of Ids fetched from the ModuleSchool to return the module names from the Modules because only the _ids are stored in the relationship table.

The above code does only does it to the level of converting the _ids to array, when I tried printing on the template nothing showed. What wrong am I to right?
解决方案
To find document with a field corresponding to at least one element of an array you can use $in :
Template.my_template.helpers({
    modules(){
        var myslug = FlowRouter.getParam('myslug');
        var mySchoolDoc = SchoolDb.findOne({slug: myslug});
        var arrayModuleSchool = ModuleSchool.find({schoolId: mySchoolDoc._id});
        // Transform the array of document into an array with only the ids
        var arrayModuleIds = [];
        arrayModuleSchool.forEach(function(moduleSchool)){
            arrayModuleIds.push(moduleSchool.moduleId);
        });
        return Modules.find({_id: {$in: arrayModuleIds}}).fetch();
    }
});
And then simply use the {{each}} tag.
<template name="my_template">
  {{#each module in modules}} 
    <p>{{module.modulename}}</p>
  {{/each}}
</template>
But if each module is attached to only one school, i suggest a simpler solution for your problem, you don't have to create a collection between school and module.

You just have to create two collections: Schools and Modules and add to the Modules documents a schoolId field.

Then your code would look like that :
Template.my_template.helpers({
    modules(){
        var myslug = FlowRouter.getParam('myslug');
        var mySchoolDoc = Schools.findOne({slug: myslug});
        return Modules.find({schoolId: mySchoolDoc._id}).fetch();
    }
});


                        
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