更新嵌套的mongodb对象失败

Question

我有以这种方式存储的mongodb数据

db.orders.insert( { _id: ObjectId().str, name: "admin", status: "online",catalog : [
        {
            "objectid" : ObjectId().str,
            "message" : "sold",
            "status" : "open"
        }
    ]})

我试图以这种方式更新db.orders.update({"_id":"5703b86df3d607cb5fa75ff3"},{$set: {"catalog.message": "added to cart"}})

这是我得到的错误消息

> db.orders.update({"_id":"5703b86df3d607cb5fa75ff3"},{$set: {"catalog.message": "added to cart"}})
WriteResult({
    "nMatched" : 0,
    "nUpserted" : 0,
    "nModified" : 0,
    "writeError" : {
        "code" : 16837,
        "errmsg" : "cannot use the part (catalog of catalog.message) to traverse the element ({catalog: [ { objectid: \"5703b86df3d607cb5fa75ff4\", message: \"sold\", status: \"open\" } ]})"
    }
})

如何更新此记录？。

Answer 1

根据MongoDB's Examples，您应该提供要更新的数组中Object的索引。由于您想要更新第一个对象，即索引0处数组中的对象，请使用：

db.orders.update(
    {"_id":"5703b86df3d607cb5fa75ff3"},
    {$set: {"catalog.0.message": "added to cart"}});