如何通过两个引用更新数组中的单个子元素(How do I update a single subelement in an array by two references)

如何通过两个引用更新数组中的单个子元素(How do I update a single subelement in an array by two references)

我有这样的学校文档结构：

{ "_id":"tnoMB2PhsPPQKcafz", // some other property here "students":[{ "student":{ "ref_id":"eaH7JsponapSWCGf6", "name":"name", "family":"family", "grade":12 }, // many other student here ]}

我想在确定的学校更新确定学生的成绩属性，但我不知道该怎么做。

例如，我有学校_id（ tnoMB2PhsPPQKcafz ）和学生ref_id（ eaH7JsponapSWCGf6 ），并希望将确定的学生成绩从12更新到18。

I have a school document structure like this:

{ "_id":"tnoMB2PhsPPQKcafz", // some other property here "students":[{ "student":{ "ref_id":"eaH7JsponapSWCGf6", "name":"name", "family":"family", "grade":12 }, // many other student here ]}

I want to update grade property for determined student in determined school but I don't know how to do this.

For example I have school _id (tnoMB2PhsPPQKcafz) and student ref_id (eaH7JsponapSWCGf6) and want to update determined student grade from 12 to 18.

最满意答案

使用$elemMatch如下：

db.school.update({"_id" : "tnoMB2PhsPPQKcafz","students":{"$elemMatch":{"student.ref_id":"eaH7JsponapSWCGf6"}}},{"$set":{"students.$.student.grade":18}})

Use $elemMatch as below :

db.school.update({"_id" : "tnoMB2PhsPPQKcafz","students":{"$elemMatch":{"student.ref_id":"eaH7JsponapSWCGf6"}}},{"$set":{"students.$.student.grade":18}})