Question

我在MongoDB中创建了几个文档：

> db.myCollection.insert( {"BUCKET": [{"Field1":"X"},{"Field2":{"A":"B","C":"D","E":"F"}}]} )

> db.myCollection.insert( {"BUCKET": [{"Field1":"Y"},{"Field2":{"G":"H","I":"J","K":"L"}}]} )

> db.myCollection.find()
{ "_id" : ObjectId("534102c492970f1b06b1edc8"), "BUCKET" : [    {   "Field1" : "X" },   {   "Field2" : {    "A" : "B",  "C" : "D",  "E" : "F" } } ] }
{ "_id" : ObjectId("5341054e92970f1b06b1edc9"), "BUCKET" : [    {   "Field1" : "T" },   {   "Field2" : {    "G" : "H",  "I" : "J",  "K" : "L" } } ] }

现在我想更新它，以便“BUCKET”的所有值都设置为[]

所以我试试这个：

db.myCollection.update({},{"BUCKET":[]}, false, false)

这部分奏效了。但它只将第一个桶改为[]：

> db.myCollection.find()
{ "_id" : ObjectId("534102c492970f1b06b1edc8"), "BUCKET" : [ ] }
{ "_id" : ObjectId("5341054e92970f1b06b1edc9"), "BUCKET" : [    {   "Field1" : "T" },   {   "Field2" : {    "G" : "H",  "I" : "J",  "K" : "L" } } ] }

所以我尝试将“multi”字段更改为true并再次尝试。但它不起作用：

> db.myCollection.update({},{"BUCKET":[]}, false, true)
multi update only works with $ operators

如何使用update（）方法更新多个子文档？

Answer 1

您需要的是$set运算符，您的更新查询才能正常运行。试试这个：

db.myCollection.update({},{$set:{"BUCKET":[]}}, false, true)

如何一次更新多个MongoDB子文档？

1 个答案: