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Source code https://github.com/zhongchengyi/zhongcy.demos/tree/master/mongo-morphia-demo Preface Morphia is a library that java uses orm to operate mongodb. But by default, when using morphia to access enum, it is accessed by name. We need to access enum by value. As shown in the figure: the schoolClassLevel1 field is accessed by enum name ...

0. purpose Download MongoDB and install it. Set password access.The MongoDB official website will download the following three installation packagesMongodb-org-server-4.2.2-1.el6.x86 × 64.rpm × mongodb services, configuration files, startup scriptsMongodb-org-shell-4.2.2-1.el6.x86 × 64.rpm 񖓿 contains shell commands related to ...

CentOS 7 Linux Installation MongoDB - yum installation 1. Build repo resources of CentOS7 Enter / etc/yum.repos.d/ directory, create mongodb-org.repo file, edit this file with vim, and add repo resources.Http://mirrors.aliyun.com/mongodb/yum/redhat/7server/mongodb-org/3.0/x86_/ is the resource address provided by Alibaba clo ...

This article combines the previous< Node learning notes Mongodb and Mongoose >Yes curd example Optimize MongoDB installation Download address of installation file:[ https://www.mongodb.com/download-center/community] To install MongoDB on Windows: https://www.runoob.com/mongodb/mongodb-window-install.html Special attention should be paid d ...

I used koa scaffold for the project, and koa router was used for routing mongodb To connect to MongoDB The knowledge point used here is async await. If you don't know how to use it, please read it first: Async await Example First, set a public method mongo.js. Here is only one query method: var MongoClient = require('mong ...

I collated Java advanced materials for free, including Java, Redis, MongoDB, MySQL, Zookeeper, Spring Cloud, Dubbo high concurrency distributed and other tutorials, a total of 30G, which needs to be collected by myself.Transfer gate: https://mp.weixin.qq.com/s/JzddfH-7yNudmkjT0IRL8Q   Exclusive lock: it is a pessimistic lock. synchronized is ...

mongodb documents contain arrays. You need to filter the qualified data in the arrays and return the result set. You can query group s or filters in two ways. Data source: { "_id" : ObjectId("5bbcc0c9a74db9804e78a157"), "uid" : "1000001", "name" : "zhangsan", "addrs" : [ { "is_query" : "1", "cit ...

I collated Java advanced materials for free, including Java, Redis, MongoDB, MySQL, Zookeeper, Spring Cloud, Dubbo high concurrency distributed and other tutorials, a total of 30G, which needs to be collected by myself.Portal: https://mp.weixin.qq.com/s/JzddfH-7yNudmkjT0IRL8Q   Chatting with friends, he mentioned that the constructor of Reent ...

Preface Share some common data cleaning methods of Mongdb Note: "Exceeded memory limit for $group, but didn't allow external sort. Pass allowDiskUse:true to opt in." causes and solutions: Reason During big data calculation and data statistics, each calculation task (job or task) will use independent and limited memory space. mongod ...

Continue to analyze the crawler data analysis articles today, let's take a look at the acquisition and analysis of NetEase's critical commodity reviews. ​ NetEase Comments Crawling Analyzing Web Pages ​ Comment Analysis Enter the official website of NetEase Strict Selection, search for "bra", and then order a commodity at will. ​ On t ...