• MongoDB Guide – 8. Specific types of queries


    Last article: MongoDB Guide – 7. Find Introduction and Query ConditionsNext article: MongoDB Guide – 9. Cursors and database commands As described in Chapter 2, MongoDB documents can use multiple types of data. Some of them have special performance when querying. 4.3.1 null The null type of behavior is a little strange. It does match itself, […]

  • Talk about Python’s built-in battery


    This article was originally published in the Public Number.【Python Cat】 Do not reproduce without authorization. Original address: https://mp.weixin.qqq.com/s/XzCqoCvcpFJt4A-E4WMqaA (1) Recently, I suddenly thought of a question:What concepts or idioms are unique to Python compared to other languages? After asking this question in the circle of friends, I got the most responses.——Pythonic。 This reply is not […]

  • Query Method of MongoDB


    Code: db.blogs.insert([ { “Author”: “Zhang San”. “Title”: “Introduction to MongoDB” “Content”: “It is a NoSQL database between relational database and non-relational database. It is written in C++. It is a high-performance document-oriented general database with agility, scalability and extensibility.” “tags”: [ “MongoDB”, “NoSQL” ], “comment”: [ { “name”: “Jack”, “detail”: “Good!”, “date”: ISODate(“2015-07-09 09:55:49”) }, […]

  • MongoDB User and Role Interpretation Series (Part I)


    This article is from the Chinese Community of MongoDB: http://www.mongo.com/ 1. Introduction This article discusses the access control required to protect MongoDB databases. Specifically, we can use these features to ensure that only authorized users can access the database. Each MongoDB user should be able to access only the data they need for their role […]

  • MongoDB Data Updating Method Dry Store


    Preface Data updating is an indispensable part of our daily operation of the database, the following article will share with you some of the dry goods of the operation of MongoDB data updating, which has a certain reference learning value for large furniture, let’s learn together. Common Functions update(<query>,<update>,<upsert>,<multi>)Where < query > denotes the condition […]

  • Differences between Redis and MongDB, Memcache and


    In preparing for the interview recently, I will summarize what I have seen. I. The difference between Redis and Memcache 1. Data type Redis is rich in data types and supports set liset and other typesMemcache supports simple data types and requires clients to handle complex objects themselves 2. Persistence Redis supports data landing persistent […]

  • MongoDB 4.0.3 Installation (centos)


    1. Download the installation package of mongoDB under / usr / local curl -O https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-4.0.3.tgz 2. Decompression: tar -zxvf mongodb-linux-x86_64-4.0.3.tgz 3. Rename mv mongodb-linux-x86_64-4.0.3.tgz mongodb-4.0.3 4. Enter folders, add data and logs folders cd mongodb-4.0.3 mkdir data mkdir logs 5. Enter the bin directory and add new configuration files cd ../bin touch mongodb.conf 6. Edit […]

  • Text Search Text Search Search Function of MongoDB Learning


    Preface MongoDB supports text search operations on text content. It provides index text index and query operation $text to complete text search. Let’s take a simple example to experience the full-text retrieval function provided by MongoDB. Method example 1. Create a new blogs collection and insert the following document. db.blogs.insert({_id:1,title:”MongoDB text search”,content:”this is a simple […]

  • Flutter’s Initial Practice to Developability


    Introduction to flutter 0. Preface: Flutter’s introductory demo has been written for a week, but it hasn’t been sorted out yet. Clean up your mood and tidy up.Following the previous introduction on react-native-wx, it imitates the Wechat UI.Because as a front-end development, there is a certain JS foundation, all write RN, it is not very […]

  • Operational monitoring of quasi-real-time data using oplog mechanism in MongoDB


    Preface Recently, there is a requirement to get the data newly inserted into MongoDB in real time, and the insertion program itself already has a set of processing logic, so it is not convenient to write related programs directly in the insertion program. Traditional databases mostly have this trigger mechanism, but Mongo has no relevant […]

  • Python Crawler Introduction Tutorial 6-100 Picture Crawling of Hummingbird Net


    1. Introduction of Hummingbird Network Pictures The National Day holiday is over, and new work has begun. Today, we continue to climb a website, which ishttp://image.fengniao.com/Hummingbird is a place where photographic bulls gather. This tutorial should be used for learning, not for commercial purposes. Unsurprisingly, hummingbird is a copyright-protected website. 2. Analysis of Hummingbird Picture […]

  • Install mongodb under windows and connect mongodb instance with node.js


    MongoDB Download Download address: https://www.mongodb.com/download-center#community. Select the Windows version to download and install it. 2. Create data catalogue after installation. MongoDB stores the data directory in the DB directory. But this data directory will not be created on its own initiative. We need to create it after installation. Note that the data directory should be […]