node.js - collection.findOne 匹配整个集合中的查询，而我需要它在对象数组中查找
问题描述
我遇到了一个场景，我需要将数据保存到 mongoDB 中，但首先我需要检查对象数组中是否存在数据。
我尝试使用collection.findOne()。这是在整个集合中搜索的方法。我需要它在 document->array of Objects->array of Objects 中匹配，在本例中为farm[ ]->device[ ]。
即，搜索该场中没有类似的设备名称。
还有其他方法吗？
后端代码
User.findOne({ 'farm.device.deviceName':deviceName }).then(device => {
if (device) {
return res.status(400).json({ "Device Name " : "Device already exists."});
} else {
...saving part
我的示例架构
[
{
"_id": "5d3ac84a86688123789e13b2",
"name": "Puja",
"email": "puja@gmail.com",
"password": "$2a$10$r17zOU1gTJvwoB.nBdRvi.qvDmsJhIlHbp//s8l0KEKgCEvbKoZAu",
"location": "Delhi",
"createdDate": "2019-07-26T09:30:50.243Z",
"farm": [
{
"location": [
"11.33,22.99"
],
"_id": "5d3ff9d68e34cb265c030819",
"farmName": "Xyz",
"description": "Testing that info is saved ",
"farmAddDate": "2019-07-30T08:03:34.247Z",
"device": [
{
"_id": "5d402def7cef9f20c8272fc4",
"deviceName": " DeviceX01",
"deviceType": " Test",
"description": " This is a test",
"deviceLocation": "11.22,33.12",
"Parameter": " temp",
"Topic": "v1/ DeviceX01/11.22,33.12/ temp"
}
]
},
{
"location": [],
"_id": "5d42d171e7ceef2a90245470",
"farmName": "Xilo",
"description": "This is test from Postman Api Request",
"farmAddDate": "2019-08-01T11:48:01.883Z",
"device": [
{
"_id": "5d441878f1877637cc712d07",
"deviceName": "Xki",
"deviceType": "Muc",
"description": "This is test for updation of specific data in a specfic farm .Test Pass",
"deviceLocation": [
"11",
"180"
],
"Parameter": "Hello Happy",
"Topic": "v1/Xki/11,180/Hello Happy"
},
{
"_id": "5d4418953968370e64c32e1f",
"deviceName": "Xki",
"deviceType": "Muc",
"description": "This is test for updation of specific data in a specfic farm .Test Pass",
"deviceLocation": [
"11",
"180"
],
"Parameter": "Hello Happy",
"Topic": "v1/Xki/11,180/Hello Happy"
},
{
"_id": "5d4425548b3cf92af46e2c9a",
"deviceName": "Xki",
"deviceType": "Muc",
"description": "This is test for updation of specific data in a specfic farm .Test Pass",
"deviceLocation": [
"11",
"180"
],
"Parameter": "Hello Happy 1",
"Topic": "sagita/5d42d171e7ceef2a90245470/Xki/11,180/Hello Happy 1"
},
{
"_id": "5d44256d8b3cf92af46e2c9b",
"deviceName": " DeviceX01",
"deviceType": " Test",
"description": " This is a test",
"deviceLocation": "11.22,33.12",
"Parameter": " set",
"Topic": "sagita/5d42d171e7ceef2a90245470/ DeviceX01/11.22,33.12/ set",
"DeviceJson": [
"{ \"$schema\": \"http: //json-schema.org/draft-04/schema#\", \"type\": \"object\", \"properties\": { \"_id\": { \"type\": \"ObjectId\" }, \"name\": { \"type\": \"string\" }, \"email\": { \"type\": \"string\" }, \"password\": { \"type\": \"string\" }, \"location\": { \"type\": \"string\" }, \"createdDate\": { \"type\": \"Date\" }, \"farm\": { \"type\": \"array\", \"items\": [ { \"type\": \"object\", \"properties\": { \"location\": { \"type\": \"array\", \"items\": [ { \"type\": \"string\" } ] }, \"_id\": { \"type\": \"ObjectId\" }, \"farmName\": { \"type\": \"string\" }, \"description\": { \"type\": \"string\" }, \"farmAddDate\": { \"type\": \"Date\" }, \"device\": { \"type\": \"array\", \"items\": [ { \"type\": \"object\", \"properties\": { \"_id\": { \"type\": \"ObjectId\" }, \"deviceName\": { \"type\": \"string\" }, \"deviceType\": { \"type\": \"string\" }, \"description\": { \"type\": \"string\" }, \"deviceLocation\": { \"type\": \"string\" }, \"Parameter\": { \"type\": \"string\" }, \"Topic\": { \"type\": \"string\" } }, \"required\": [ \"_id\", \"deviceName\", \"deviceType\", \"description\", \"deviceLocation\", \"Parameter\", \"Topic\" ] } ] } }, \"required\": [ \"location\", \"_id\", \"farmName\", \"description\", \"farmAddDate\", \"device\" ] }, { \"type\": \"object\", \"properties\": { \"location\": { \"type\": \"array\", \"items\": {} }, \"_id\": { \"type\": \"ObjectId\" }, \"farmName\": { \"type\": \"string\" }, \"description\": { \"type\": \"string\" }, \"farmAddDate\": { \"type\": \"Date\" }, \"device\": { \"type\": \"array\", \"items\": [ { \"type\": \"object\", \"properties\": { \"_id\": { \"type\": \"ObjectId\" }, \"deviceName\": { \"type\": \"string\" }, \"deviceType\": { \"type\": \"string\" }, \"description\": { \"type\": \"string\" }, \"deviceLocation\": { \"type\": \"array\", \"items\": [ { \"type\": \"string\" }, { \"type\": \"string\" } ] }, \"Parameter\": { \"type\": \"string\" }, \"Topic\": { \"type\": \"string\" } }, \"required\": [ \"_id\", \"deviceName\", \"deviceType\", \"description\", \"deviceLocation\", \"Parameter\", \"Topic\" ] }, { \"type\": \"object\", \"properties\": { \"_id\": { \"type\": \"ObejctId\" }, \"deviceName\": { \"type\": \"string\" }, \"deviceType\": { \"type\": \"string\" }, \"description\": { \"type\": \"string\" }, \"deviceLocation\": { \"type\": \"array\", \"items\": [ { \"type\": \"string\" }, { \"type\": \"string\" } ] }, \"Parameter\": { \"type\": \"string\" }, \"Topic\": { \"type\": \"string\" } }, \"required\": [ \"_id\", \"deviceName\", \"deviceType\", \"description\", \"deviceLocation\", \"Parameter\", \"Topic\" ] }, { \"type\": \"object\", \"properties\": { \"_id\": { \"type\": \"ObjectId\" }, \"deviceName\": { \"type\": \"string\" }, \"deviceType\": { \"type\": \"string\" }, \"description\": { \"type\": \"string\" }, \"deviceLocation\": { \"type\": \"array\", \"items\": [ { \"type\": \"string\" }, { \"type\": \"string\" } ] }, \"Parameter\": { \"type\": \"string\" }, \"Topic\": { \"type\": \"string\" } }, \"required\": [ \"_id\", \"deviceName\", \"deviceType\", \"description\", \"deviceLocation\", \"Parameter\", \"Topic\" ] }, { \"type\": \"object\", \"properties\": { \"_id\": { \"type\": \"ObjectId\" }, \"deviceName\": { \"type\": \"string\" }, \"deviceType\": { \"type\": \"string\" }, \"description\": { \"type\": \"string\" }, \"deviceLocation\": { \"type\": \"string\" }, \"Parameter\": { \"type\": \"string\" }, \"Topic\": { \"type\": \"string\" }, \"DeviceJson\": { \"type\": \"array\", \"items\": [ { \"type\": \"string\" } ] } }, \"required\": [ \"_id\", \"deviceName\", \"deviceType\", \"description\", \"deviceLocation\", \"Parameter\", \"Topic\", \"DeviceJson\" ] } ] } }, \"required\": [ \"location\", \"_id\", \"farmName\", \"description\", \"farmAddDate\", \"device\" ] }, { \"type\": \"object\", \"properties\": { \"location\": { \"type\": \"array\", \"items\": [ { \"type\": \"string\" } ] }, \"_id\": { \"type\": \"ObjectId\" }, \"farmName\": { \"type\": \"string\" }, \"description\": { \"type\": \"string\" }, \"farmAddDate\": { \"type\": \"Date\" }, \"device\": { \"type\": \"array\", \"items\": [ { \"type\": \"object\", \"properties\": { \"_id\": { \"type\": \"ObjectId\" }, \"deviceName\": { \"type\": \"string\" }, \"deviceType\": { \"type\": \"string\" }, \"description\": { \"type\": \"string\" }, \"deviceLocation\": { \"type\": \"array\", \"items\": [ { \"type\": \"string\" }, { \"type\": \"string\" } ] }, \"Parameter\": { \"type\": \"string\" }, \"Topic\": { \"type\": \"string\" } }, \"required\": [ \"_id\", \"deviceName\", \"deviceType\", \"description\", \"deviceLocation\", \"Parameter\", \"Topic\" ] } ] } }, \"required\": [ \"location\", \"_id\", \"farmName\", \"description\", \"farmAddDate\", \"device\" ] } ] }, \"__v\": { \"type\": \"integer\" }, \"farmModifyDate\": { \"type\": \"Timestamp\" }, \"lastModified\": { \"type\": \"Timestamp\" }, \"deviceModifyDate\": { \"type\": \"Timestamp\" }, \"deviceModified\": { \"type\": \"Timestamp\" } }, \"required\": [ \"_id\", \"name\", \"email\", \"password\", \"location\", \"createdDate\", \"farm\", \"__v\", \"farmModifyDate\", \"lastModified\", \"deviceModifyDate\", \"deviceModified\" ] }"
]
}
]
},
{
"location": [
"11.22,65.33"
],
"_id": "5d492a4a1294110f64196b2d",
"farmName": "Durgapur",
"description": "This is a test for frontend to backend",
"farmAddDate": "2019-08-06T07:20:42.654Z",
"device": [
{
"_id": "5d4bd62900b433276c2845af",
"deviceName": "Farm @2 Device 001",
"deviceType": "Intel Edision",
"description": "This is a test for creation of Data Bucket of Topic",
"deviceLocation": [
"12.33",
"56.33"
],
"Parameter": "Temperature",
"Topic": "sagita/model/5d492a4a1294110f64196b2d/Farm @2 Device 001/12.33,56.33/Temperature"
}
]
}
],
"__v": 0,
"lastModified": "2019-12-04T06:59:17.431Z",
"farmModifyDate": "6764284414131175425",
"deviceModifyDate": "6720517743902195713",
"deviceModified": "6766475118035075073"
}
]
解决方案
您可以使查询更具体——例如也可以通过 userId 匹配——以将搜索限制为始终检查 1 个特定文档。
如果您也想将其限制在特定农场，您可以查看 $elemMatch - 它可能有助于匹配特定农场中的 2 个条件。
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