javascript - 如何使用另一个集合中的字段值更新 Mongodb 集合中的文档

Question

我有两个收藏1) 平面图_备份。 该文档的结构如下所示:-

{
    "_id" : ObjectId("5877e18a88db272b578572bd"),
    "floorplans" : [ 
        {
            "name" : "Campus Center - Atrium",
            "uuid" : NumberLong(3),
            "cameras" : []
        }, 
        {
            "name" : "Campus Center - Bridge ",
            "uuid" : NumberLong(4),
            "cameras" : []
        }, 
        {
            "name" : "Campus Center - Top",
            "uuid" : NumberLong(5),
            "cameras" : []
        }, 
        {
            "name" : "Performance Dining Hall",
            "uuid" : NumberLong(6),
            "cameras" : []
        }, 
        {
            "name" : "Main Kitchen",
            "uuid" : NumberLong(7),
            "cameras" : []
        }, 
        {
            "name" : "OrgChart - Board of Trustees",
            "uuid" : NumberLong(8),
            "cameras" : []
        }, 
        {
            "name" : "OrgChart - Academic Affairs",
            "uuid" : NumberLong(9),
            "cameras" : []
        }, 
        {
            "name" : "OrgChart - Admissions",
            "uuid" : NumberLong(10),
            "cameras" : []
        }, 
        {
            "name" : "OrgChart - Athletics",
            "uuid" : NumberLong(11),
            "cameras" : []
        }, 
        {
            "name" : "OrgChart - Financial",
            "uuid" : NumberLong(14),
            "cameras" : []
        }, 
        {
            "name" : "OrgChart - HR",
            "uuid" : NumberLong(15),
            "cameras" : []
        }, 
        {
            "name" : "OrgChart - Institutional",
            "uuid" : NumberLong(16),
            "cameras" : []
        }, 
        {
            "name" : "OrgChart - IT",
            "uuid" : NumberLong(17),
            "cameras" : []
        }, 

        {
            "name" : "OrgChart - Student Success",
            "uuid" : NumberLong(20),
            "cameras" : []
        }, 
        {
            "name" : "OrgChart - Student Life",
            "uuid" : NumberLong(21),
            "cameras" : []
        }
    ],
    "userid" : "user-56cb3c4c0c953470865336",
    "firstviewhost" : undefined
}

2) 平面图。文档结构

{
    "_id" : ObjectId("589025b03422cafc09913363"),
    "userid" : "user-56cb3c4c0c953470865336",
    "firstviewhost" : "dean.vizsafe.com"
}

我想通过匹配两个集合的用户 ID，将 Floorpla_backup 中的firstviewhost 更新为值“dean.vizsafe.com”。

使用的 JavaScript 代码是:-

db.floorplan_backup.find().forEach(function (doc1) {
    var doc2 = db.floorplan.find({ userid: doc1.userid }, { firstviewhost: 1 });
    if (doc2 != null) {
        doc1.firstviewhost = doc2.firstviewhost;
        db.floorplan_backup.save(doc1);
    }
});

但是没有给我想要的结果集。你能让我知道这有什么问题吗？

Answer 1

doc2 是一个数组。使用findOne获取对象。

db.floorplan_backup.find().forEach(function (doc1) {
    var doc2 = db.floorplan.findOne({ userid: doc1.userid }, { firstviewhost: 1 });
    if (doc2 != null) {
        doc1.firstviewhost = doc2.firstviewhost;
        db.floorplan_backup.save(doc1);
    }
});