英文:
Any way to insert fields only if they don't already exist in MongoDB?
问题
我尝试了一些我找到的解决方案，但我不明白这应该如何工作（我是Mongo的新手）。我有一个看起来像这样的文档：
{
"_id": {
"$oid": "63ef95daf324e5a26354eb61"
},
"idCarga": "6182944",
"12121212121212": {
"info1": "hello",
"info2": "goodbye"
},
"13131313131313": {
"info1": "hello",
"info2": "goodbye"
}
}
我的目标是：
- 如果我尝试使用新的产品ID字段（如15151515151515）更新文档，它将作为新字段插入。
- 如果我尝试使用已经存在的产品ID（如13131313131313）更新文档，什么都不会发生（不会插入或更新任何内容）。
我使用$exists运算符与upsert选项得到了一些结果。但我必须插入如此多的产品ID，这似乎是一个不可行的选项。是否有办法只使用一个文档来实现这一目标？还是我必须将其拆分为两个集合？先感谢您。
英文:
I've tried some solutions i've found but im not getting how this is supposed to work (im new to mongo). i have a document that looks like this:
{
"_id": {
"$oid": "63ef95daf324e5a26354eb61"
},
"idCarga": "6182944",
"12121212121212": {
"info1": "hello",
"info2": "goodbye"
},
"13131313131313": {
"info1": "hello",
"info2": "goodbye"
}
}
My goal is to:
- If i try to update the document with a new product ID field (like 15151515151515), it gets inserted as a new field.
- If i try to update the document with an already existing prod ID (like 13131313131313), nothing happens (dont insert or update anything).
I got some results with the $exists operator paired with upsert option. But i have to insert so many product IDs it seems like an unviable option. Is there any way to do this with only one document per "idCarga"? Or do i have to separate this into 2 collections? Thanks in advance.
答案1
得分: 0
以下是代码部分的中文翻译：
db.collection.update({
<您的条件>
},[
{
$set: {
"<您的ID>": {
"$ifNull": [
"$<您的ID>",
{
<您的新子文档>
}
]
}
}
}
])
英文:
Simply do a $set with $ifNull
db.collection.update({
<your criteria>
},[
{
$set: {
"<your id>": {
"$ifNull": [
"$<your id>",
{
<your new sub doc>
}
]
}
}
}
])
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