如何从mongodb中的字段创建键值对

Question

我有一些数据的结构如下：

"location_identifiers": [
{
"permalink": "olivette-missouri",
"uuid": "e1774b1c-634d-4ea4-1414-cd8be15df631",
"location_type": "city",
"entity_def_id": "location",
"value": "Olivette"
},
{
"permalink": "missouri-united-states",
"uuid": "51a065b8-05d5-1a28-3fcd-1ad143f1f725",
"location_type": "region",
"entity_def_id": "location",
"value": "Missouri"
}

我想把它重组成这样，我使用的是mongodb指南针：

"location_identifiers": [
{
"city": "Olivette",
"region": "Missouri"
}
]

我试过放松和项目查询，但我被卡住了，任何帮助都将不胜感激。

Answer 1

使用$arrayToObject

db.collection.aggregate([
{
"$match": {}
},
{
"$set": {
"location_identifiers": [
{
"$arrayToObject": {
"$map": {
"input": "$location_identifiers",
"as": "item",
"in": {
k: "$$item.location_type",
v: "$$item.value"
}
}
}
}
]
}
}
])

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