mongodb

Insert large record into mongodb using mongo shell

由 老子叫甜甜 提交于 2021-02-15 07:50:13
问题 I'm trying to insert large polygon array into my collection. I'm using following command to insert the data... db.geoPolygonData.insert({"polygonName":"location1", "polygons":{"type":"Polygon", coordinates:[[[ 17.60083012593064, 78.18557739257812], [ 17.16834652544664, 78.19381713867188], [ 17.17490690610013, 78.739013671875], [ 17.613919673106714, 78.73489379882812],[ 17.60083012593064, 78.18557739257812]]]}}); WriteResult({ "nInserted" : 1 }) Problem: when the polygon array size is too

Updating data type to an Object in mongoDB

由 坚强是说给别人听的谎言 提交于 2021-02-15 07:37:33
问题 I have changed one of the fields of my collection in mongoDB from an array of strings to an array of object containing 2 strings. New documents get inserted without any problem, but when a get method is called to get , querying all the documents I get this error: Failed to decode 'Students'. Decoding 'photoAddresses' errored with: readStartDocument can only be called when CurrentBSONType is DOCUMENT, not when CurrentBSONType is STRING. photoAddresses is the field that was changed in Students.

MongoDB — Setting a conditional statement in .find()

由 那年仲夏 提交于 2021-02-15 07:36:29
问题 for aggregate, $cond can be used to form an if-statement. I'm wonder if there's a similar function for .find() When I tried using $cond in find(), I get "unknown top level operator: $cond" I'm trying to do the following (in pseudo code): if condition is True: set filter for find to thing_1 else: set filter for find to thing_2 回答1: If you are on Mongo 3.6 or greater, you could try using the $expr operator. Which would then allow you to use $cond . $expr Allows the use of aggregation

How to concatenate string results from multiple MongoDB records into a single result in MongoDB?

由 删除回忆录丶 提交于 2021-02-15 07:12:16
问题 Assuming the following records: { text: "foo"}, { text: "bar"} How can I get a result such as: results: "foo bar" The closest I am getting to it is to use $addToSet but this just creates an array with the results instead of a single string which is what I really want. results: [ "foo", "bar" ] Using Mongo 3.4 回答1: Use $group to get an array from all the documents and then $reduce with $concat to get one string: db.col.aggregate([ { $group: { _id: null, text: { $push: "$text" } } }, { $project

How to concatenate string results from multiple MongoDB records into a single result in MongoDB?

由 我怕爱的太早我们不能终老 提交于 2021-02-15 07:10:22
问题 Assuming the following records: { text: "foo"}, { text: "bar"} How can I get a result such as: results: "foo bar" The closest I am getting to it is to use $addToSet but this just creates an array with the results instead of a single string which is what I really want. results: [ "foo", "bar" ] Using Mongo 3.4 回答1: Use $group to get an array from all the documents and then $reduce with $concat to get one string: db.col.aggregate([ { $group: { _id: null, text: { $push: "$text" } } }, { $project

How to perform addToSet using Go official driver?

由 别来无恙 提交于 2021-02-15 07:09:15
问题 I need to do addToSet operation using official Go MongoDB driver. In MongoDB we have some docs: { _id: 2, item: "cable", tags: [ "electronics", "supplies" ] } Then to perform addToSet : db.inventory.update( { _id: 2 }, { $addToSet: { tags: { $each: [ "camera", "electronics", "accessories" ] } } } ) Result: { _id: 2, item: "cable", tags: [ "electronics", "supplies", "camera", "accessories" ] } 回答1: $addToSet is an update operation, if you want to update a single document, you may use the

How to perform addToSet using Go official driver?

由 守給你的承諾、 提交于 2021-02-15 07:08:34
问题 I need to do addToSet operation using official Go MongoDB driver. In MongoDB we have some docs: { _id: 2, item: "cable", tags: [ "electronics", "supplies" ] } Then to perform addToSet : db.inventory.update( { _id: 2 }, { $addToSet: { tags: { $each: [ "camera", "electronics", "accessories" ] } } } ) Result: { _id: 2, item: "cable", tags: [ "electronics", "supplies", "camera", "accessories" ] } 回答1: $addToSet is an update operation, if you want to update a single document, you may use the

I need to retrieve MongoDB's object just with filtered's array item

由 大城市里の小女人 提交于 2021-02-15 07:05:44
问题 I'm needing to retrieve just with two dates, all the documents from my MongoDB's collection, with the filtered items from the array. This is an example of 2 of my documents; { "_id" : ObjectId("5f18fa823406b7000132d097"), "last_date" : "22/07/2020 23:48:32", "history_dates" : [ "22/07/2020 23:48:32", "22/07/2020 00:18:53", "23/07/2020 00:49:12", "23/07/2020 01:19:30" ], "hostname" : "MyHostname1", "ip" : "142.0.111.79", "component" : "C:\\Windows\\System32\\es-ES\\KernelBase.dll.mui",

Cannot connect to Mongo Atlas using VPC peering from GCP cluster

由 天大地大妈咪最大 提交于 2021-02-15 05:32:11
问题 I am trying to connect a Java app running on a GCP Kubernetes engine cluster, with a Mongo Atlas cluster (M20). Before, it worked fine, when I didn't have VPC Peering turned on and I was using the regular connection string. But I am trying to use VPC Peering now, with the default VPC network in my GCP project. I followed the steps in https://docs.atlas.mongodb.com/security-vpc-peering/. I chose Atlas CIDR of 192.168.0.0/18 (b/c "The Atlas CIDR block must be at least a /18"), and after linking

写给Web前端开发的后端指南

由 空扰寡人 提交于 2021-02-14 18:51:39
前言 在若干次前的一场面试，面试官看我做过 python 爬虫/后端 的工作，顺带问了我些后端相关的问题： 你觉得什么是后端？ 送命题 。当时脑瓦特了，答曰： 逻辑处理和数据增删改查。。。 当场被怼得体无完肤，羞愧难当。事后再反思这问题，结合资料总结了一下。发现自己学过的 Redis 、 Elasticsearch 和 DNS 等其实都属于后端知识体系范畴。 在本文中，我将尝试 总结前端须知的后端体系入门 。 无论你的动机是什么，这个体系里都有你想要了解或学习的东西： 存储和服务如何结合在一起？ 什么时候（或为什么）我需要用到这个？ 全栈之路该怎么走？ 各技术的主流框架选择 本文目录 ： 1. Web / Application Servers 2. 负载均衡器: Load Balancer 3. 域名解析系统，DNS 4. HTTPS / SSL证书 5. 数据库，Database 6. Blob / 文件存储 7. 内容分发网络（CDN） 8. 缓存服务：Caching Service 9. 消息队列：Message queue 1. Web / Application Servers Web Servers 服务器：Web服务器，使用 http 协议向Web提供内容。 Application Servers ：应用程序服务器，托管并公开业务逻辑和进程。 1.1 服务器端语言
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