Question

我有一个类似的事件集合：

{title: "Some Title", description: "Some Description", products: [{_id: "owkaowakdowakd", quantity: 15}]}

我想向产品数组的所有元素添加一个带有空数组的“保留”字段。要获得此结果：

{title: "Some Title", description: "Some Description", products: [{_id: "owkaowakdowakd", quantity: 15, reserved: [] }]}

查看文档，您可以使用$ []运算符对数组的所有元素进行更改。 https://docs.mongodb.com/manual/reference/operator/update/positional-all/#positional-update-all

db.events.updateMany( {"products.reserved": {$exists: false}}, {$set: {"products.$[].reserved": []}})

但这会返回一个错误：

2019-12-17T16:03:43.399+0000 E  QUERY    [js] WriteError({
    "index" : 0,
    "code" : 28,
    "errmsg" : "Cannot create field 'reserved' in element {0: null}",
    "op" : {
        "q" : {
            "products.reserved" : {
                "$exists" : false
            }
        },
        "u" : {
            "$set" : {
                "products.$[].reserved" : [ ]
            }
        },
        "multi" : true,
        "upsert" : false
    }
}) :
WriteError({
    "index" : 0,
    "code" : 28,
    "errmsg" : "Cannot create field 'reserved' in element {0: null}",
    "op" : {
        "q" : {
            "products.reserved" : {
                "$exists" : false
            }
        },
        "u" : {
            "$set" : {
                "products.$[].reserved" : [ ]
            }
        },
        "multi" : true,
        "upsert" : false
    }
})

我也试图修改每个元素的数量，因为它已经存在，但是返回相同的错误！ “无法创建字段“数量” ...”

Answer 1

希望这会有所帮助

Add Fields

Mongodb位置更新所有$ []似乎不起作用

1 个答案: