概述：
我正在处理的文档中有两个嵌套数组 - contentMetaData＆amp; text_content。
在contentMetaData内，我们有text_content和content_flag。根据{{1}}的值，我需要隐藏content_flag中的特定字段。
要求：
text_content为真，则content_flag应该只有一个孩子 - text_content。text_note为假，content_flag应该只有一个孩子 - text_content。使用的版本： Mongo 2.6
示例文档：
text_description示例输出：
{
"_id": ObjectId("56f8dd19e4b0365115927b0f"),
"contentId": "cbc91805-2faa-4eff-8f84-02547173c152",
"contentMetaData": [
{
"_id": "1574b58f-b7fa-4cd5-b34f-98beeb657c97",
"name": "text_content",
"attributes": [],
"children": [
{
"_id": "97340ecf-fdbd-41e5-a6b2-01cc542f16ee",
"name": "text_note",
"value": "abc",
"type": "java.lang.String",
"attributes": [],
"children": [],
"noOfChildren": 0,
"positionIndex": 1
},
{
"_id": "19c5a3fb-54a2-4368-a89d-ea1d2554402d",
"name": "text_description",
"value": "def",
"type": "java.lang.String",
"attributes": [],
"children": [],
"noOfChildren": 0,
"positionIndex": 2
}
],
"noOfChildren": 2,
"positionIndex": 1
},
{
"_id": "4e8ef7c9-cffd-4b36-9109-89b263dff3c8",
"name": "content_flag",
"value": "true",
"type": "java.lang.String",
"attributes": [],
"children": [],
"noOfChildren": 0,
"positionIndex": 2
}
]
}
我尝试使用{
"_id": ObjectId("56f8dd19e4b0365115927b0f"),
"contentId": "cbc91805-2faa-4eff-8f84-02547173c152",
"contentMetaData": [
{
"_id": "1574b58f-b7fa-4cd5-b34f-98beeb657c97",
"name": "text_content",
"attributes": [],
"children": [
{
"_id": "97340ecf-fdbd-41e5-a6b2-01cc542f16ee",
"name": "text_note",
"value": "abc",
"type": "java.lang.String",
"attributes": [],
"children": [],
"noOfChildren": 0,
"positionIndex": 1
}
],
"noOfChildren": 2,
"positionIndex": 1
},
{
"_id": "4e8ef7c9-cffd-4b36-9109-89b263dff3c8",
"name": "content_flag",
"value": "true",
"type": "java.lang.String",
"attributes": [],
"children": [],
"noOfChildren": 0,
"positionIndex": 2
}
]
}
但它没有用。我尝试使用$map，但无法以所需格式$unwind数据。
示例Mongo代码：
$push我是Mongo的新手。有人可以帮我解决这个问题吗？
答案 0 :(得分：1)
您可以尝试以下聚合。
$map与$setDifference结合使用，可以提取text_content和content_flag数组。
$unwind到content_flag文档。
$map将text_content和$map中的当前值与$setDifference结合使用，以便根据条件过滤children。
$setUnion将text_content和content_flag数组加入contentMetaData
db.collection.aggregate({
$project: {
_id: 1,
contentId: 1,
text_content: {
"$setDifference": [{
"$map": {
"input": "$contentMetaData",
"as": "text",
"in": {
"$cond": [{
$eq: ['$$text.name', "text_content"]
},
"$$text",
false
]
}
}
},
[false]
]
},
content_flag: {
"$setDifference": [{
"$map": {
"input": "$contentMetaData",
"as": "content",
"in": {
"$cond": [{
$eq: ['$$content.name', "content_flag"]
},
"$$content",
false
]
}
}
},
[false]
]
}
}
}, {
$unwind: "$content_flag"
}, {
$project: {
"_id": 1,
contentId: 1,
"contentMetaData": {
$setUnion: [{
$map: {
input: "$text_content",
as: "text",
in: {
"_id": "$$text._id",
"name": "$$text.name",
"attributes": "$$text.attributes",
"noOfChildren": "$$text.noOfChildren",
"positionIndex": "$$text.positionIndex",
"children": {
"$setDifference": [{
"$map": {
"input": "$$text.children",
"as": "child",
"in": {
"$cond": [{
"$cond": [{
$eq: ["$content_flag.value", "true"]
}, {
$eq: ["$$child.name", "text_note"]
}, {
$eq: ["$$child.name", "text_description"]
}]
},
"$$child",
false
]
}
}
},
[false]
]
}
}
}
},
["$content_flag"]
]
}
}
})
<强>更新：
$map与$setDifference结合使用以提取content_flag数组。
$unwind到content_flag文档。
$redact一次浏览一个文档级别，并递归查找name字段，并对条件执行$$DESCEND和$$PRUNE。
$project格式化最终回复。
db.collection.aggregate({
$project: {
_id: 1,
contentId: 1,
contentMetaData: 1,
content_flag: {
"$setDifference": [{
"$map": {
"input": "$contentMetaData",
"as": "content",
"in": {
"$cond": [{
$eq: ['$$content.name', "content_flag"]
},
"$$content",
false
]
}
}
},
[false]
]
}
}
}, {
$unwind: "$content_flag"
}, {
$redact: {
$cond: [{
$or: [{
$eq: ["$name", "text_content"]
}, {
$not: "$name"
}, {
$eq: ["$name", "content_flag"]
}, {
$and: [{
$eq: ["$name", "text_note"]
}, {
$eq: ["$$ROOT.content_flag.value", "true"]
}]
}, {
$and: [{
$eq: ["$name", "text_description"]
}, {
$eq: ["$$ROOT.content_flag.value", "false"]
}]
}]
},
"$$DESCEND",
"$$PRUNE"
]
}
}, {
$project: {
_id: 1,
contentId: 1,
contentMetaData: 1
}
});