Meteor mongo 更新嵌套数组

Question

示例文档：

{
"_id" : "5fTTdZhhLkFXpKvPY",
"name" : "example",
"usersActivities" : [ 
    {
        "userId" : "kHaM8hL3E3As7zkc5",
        "startDate" : ISODate("2015-06-01T00:00:00.000Z"),
        "endDate" : ISODate("2015-06-01T00:00:00.000Z")
    }
]
}

我是 mongoDB 的新人，我阅读了有关更新嵌套数组的其他问题，但我无法正确完成。我想要做的是更改具有给定 userId 的用户的 startDate 和 endDate。我的问题是它总是将新对象推送到数组而不是使用给定的 userId 更改对象。

Activity.update( 
    _id: activityId, usersActivities: {
         $elemMatch: {
             userId: Meteor.userId()
         }
     }},
    {
        $push: {
            'usersActivities.$.startDate': start,
            'usersActivities.$.endDate': end
         }
    }
);

我很乐意提供帮助。

Answer 1

所以这里首先要说的是$elemMatch is not required in your case as you only want to match on a single array property. You use that operator when you need "two or more" properties from the same array element to match your conditions. Otherwise you just use "dot notation"作为标准。

第二种情况是 $push, where that particular operator means to "add" elements to the array. In your case you just want to "update" so the correct operator here is $set:

Activity.update(
    { "_id": activityId, "usersActivities.userId": Meteor.userId() },
    {
        "$set": {
            'usersActivities.$.startDate': start,
            'usersActivities.$.endDate': end
        }
    }
)

所以这里的 positional $ operator 匹配数组元素中的 "found index" 并允许 $set 运算符 "change" 在 [=27= 处匹配的元素].

Answer 2

"What if Meteor.userId() does not exist, how to insert the whole of object with userID, startDate and endDate? – justdiehard Jun 14 at 20:20"

如果你尝试添加新的，你应该看看 Meteor Accounts 包，有像

这样的方法

Accounts.createUser(YOU_USER_SCHEME)

Meteor mongo 更新嵌套数组

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