我在聊天中有 Chat
集合中的以下文档,其中包含 messages
和 members
数组。
对于每条消息,都会有一个状态字段,用于存储关于用户的发送和读取时间戳。
{
"_id" : ObjectId("60679797b4365465745065b2"),
"members" : [
ObjectId("604e02033f4fc07b6b82771c"),
ObjectId("6056ef4630d7b103d8043abd"),
ObjectId("6031e3dce8934f11f8c9a79c")
],
"isGroup" : true,
"createdAt" : 1617401743720.0,
"updatedAt" : 1617436504453.0,
"messages" : [
{
"createdAt" : 1617401743719.0,
"updatedAt" : 1617401743719.0,
"_id" : ObjectId("60679797b4365465745065b3"),
"body" : "This is test message",
"senderId" : ObjectId("6031e3dce8934f11f8c9a79c"),
"status" : []
}
]
}
因此,我想将以下数据插入到 messages.status
数组中,以了解成员何时接收/读取消息。
{
receiverId: <member of chat>
deliveredAt: <timestamp>
readAt: <timestamp>
}
如何编写查询,通过使用现有字段中的数据,为status
数组中的每个成员(发件人除外)插入上述json?
这样,在查询之后,文档应该是这样的:
{
"_id" : ObjectId("60679797b4365465745065b2"),
"members" : [
ObjectId("604e02033f4fc07b6b82771c"),
ObjectId("6056ef4630d7b103d8043abd"),
ObjectId("6031e3dce8934f11f8c9a79c")
],
"isGroup" : true,
"createdAt" : 1617401743720.0,
"updatedAt" : 1617436504453.0,
"messages" : [
{
"createdAt" : 1617401743719.0,
"updatedAt" : 1617401743719.0,
"_id" : ObjectId("60679797b4365465745065b3"),
"body" : "This is test message",
"senderId" : ObjectId("6031e3dce8934f11f8c9a79c"),
"status" : [{
"receiverId": ObjectId("604e02033f4fc07b6b82771c")
"deliveredAt": <timestamp>
"readAt": <timestamp>
}, {
"receiverId": ObjectId("6056ef4630d7b103d8043abd")
"deliveredAt": <timestamp>
"readAt": <timestamp>
}]
}
]
}
我可以对静态数据执行此操作。
链接:https://mongoplayground.net/p/LgVPfRoXL5p
为了便于理解:我必须映射 members
数组并将其插入到 status
的 messages
字段
MongoDB 版本: 4.0.5
答案 0 :(得分:1)
您可以使用 $function 运算符定义自定义函数以实现 MongoDB 查询语言不支持的行为。因此,与 updates-with-aggregate-pipeline 和 $function
一起,您可以仅使用接收者的详细信息更新 messages.status
数组,如下所示:
注意:仅适用于 MongoDB 版本 >= 4.4。
试试这个:
let messageId = ObjectId("60679797b4365465745065b3");
db.chats.update(
{ "messages._id": messageId },
[
{
$set: {
"messages": {
$map: {
input: "$messages",
as: "message",
in: {
$cond: {
if: { $eq: ["$$message._id", messageId] },
then: {
$function: {
body: function (message, members) {
message.status = [];
for (let i = 0; i < members.length; i++) {
if (message.senderId.valueOf() != members[i].valueOf()) {
message.status.push({
receiverId: members[i],
deliveredAt: new Date().getTime(),
readAt: new Date().getTime()
})
}
}
return message;
},
args: ["$$message", "$members"],
lang: "js"
}
},
else: "$$message"
}
}
}
}
}
}
]
);
输出:
{
"_id" : ObjectId("60679797b4365465745065b2"),
"members" : [
ObjectId("604e02033f4fc07b6b82771c"),
ObjectId("6056ef4630d7b103d8043abd"),
ObjectId("6031e3dce8934f11f8c9a79c")
],
"isGroup" : true,
"createdAt" : 1617401743720,
"updatedAt" : 1617436504453,
"messages" : [
{
"_id" : ObjectId("60679797b4365465745065b3"),
"createdAt" : 1617401743719,
"updatedAt" : 1617401743719,
"body" : "This is test message",
"senderId" : ObjectId("6031e3dce8934f11f8c9a79c"),
"status" : [
{
"receiverId" : ObjectId("604e02033f4fc07b6b82771c"),
"deliveredAt" : 1617625735318,
"readAt" : 1617625735318
},
{
"receiverId" : ObjectId("6056ef4630d7b103d8043abd"),
"deliveredAt" : 1617625735318,
"readAt" : 1617625735318
}
]
},
{
"_id" : ObjectId("60679797b4365465745065b4"),
"createdAt" : 1617401743719,
"updatedAt" : 1617401743719,
"body" : "This is test message",
"senderId" : ObjectId("6031e3dce8934f11f8c9a79d"),
"status" : [ ]
}
]
}
答案 1 :(得分:0)
演示 - https://mongoplayground.net/p/FoOvxXp6nji
https://docs.mongodb.com/manual/reference/operator/update/positional-filtered/
<块引用>过滤后的位置运算符 $[] 标识与更新操作的 arrayFilters 条件匹配的数组元素,例如
db.collection.update({
"messages.senderId": "6031e3dce8934f11f8c9a79c" // query
},
{
"$push": {
"messages.$[m].status": [ // push into the matching element of arrayFilters
{
"receiverId": ObjectId("604e02033f4fc07b6b82771c")
},
{
"receiverId": ObjectId("6056ef4630d7b103d8043abd")
}
]
}
},
{
arrayFilters: [
{
"m.senderId": "6031e3dce8934f11f8c9a79c" // matches array element where senderId is 6031e3dce8934f11f8c9a79c
}
]
})
注意 - 将索引添加到 messages.senderId
以提高性能