node operation mongodb database

install cnpm install mongodb Create database //create object var MongoClient = require('mongodb').MongoClient; //Configure url and port var url = "mongodb://localhost:27017/runoob"; //link MongoClient.connect(url, function(err, db) { if (err) throw err; console.log("Database created!"); db.close(); ...

Posted on Sun, 05 Apr 2020 01:36:45 -0400 by nyi8083

Accessing big data objects with PDO

Large object refers to the data with large capacity such as pictures stored in the database. Generally, pictures are rarely stored in the database. First, create a table to access and store images: create table images(id int not null auto_increment primary key,mimetype char(30),data blob); There are four source fil ...

Posted on Sun, 05 Apr 2020 01:27:22 -0400 by troy_mccormick

Batch processing of JDBC

Batch processing of JDBC: 1) batch processing: a lot of data is processed at one time. Explanation: sometimes it is necessary to send a batch of sql statements to the database for execution. In this case, it is necessary to avoid sending and executing one by one to the database, The batch processing mechanism of JDBC should be adopted to impro ...

Posted on Sun, 05 Apr 2020 00:58:46 -0400 by Merdok

Configurable message template encapsulation

Background: there are often some scenarios in the project that need to send messages to notifications (not message queues...). There are many forms of messages, such as mail, such as nails. The content of the message is determined by the business and may include dynamic parameters. The receiver of the message may be a fixed person or a dynam ...

Posted on Sat, 04 Apr 2020 23:47:07 -0400 by dennyx

CentOS7+mysql5.6 configuration master slave

1, Installation environment Operating system: centos-7-x86_-dvd-1611.iso Database version: mysql-5.6.39-linux-glibc2.12-x86_.tar.gz Database address: 192.168.2.1 (main) 192.168.2.2 (from)   MySQL was installed before and after 5.6 in a different way.   The mysql installation is self-organized. The master-slave configuration is based on ...

Posted on Sat, 04 Apr 2020 20:43:40 -0400 by Kitty

Probe into ReadType of scan in HBase

background knowledge Linux level linux provides different functions for reading files, with the following references: When a random read-write operation is performed on the same file handle (under Windows) or file descriptor (under Linux), there are two steps to locate and read/write the file pointer, but since this is not an atomic operation, ...

Posted on Sat, 04 Apr 2020 17:10:10 -0400 by MrAlaska

Spring boot connects Redis to implement HMSET operation

This article records using spring boot starter Redis to access Redis. The Redis related configuration files are placed in the application.yml file in the Resources directory, as shown below: spring: profiles: dev,default,test redis: database: 1 host: 192.168.107.253 #redis test server port: 6379 First, add dependency in pom.xml: ...

Posted on Sat, 04 Apr 2020 16:47:28 -0400 by bigwatercar

Using DBUtils to write general DAO

Main problems encountered: ->DAO can be implemented in more than JDBC, so you need to write a DAO interface, and then use JDBC to implement the method ->If you want to be generic, you must be generic. However, some methods in queryRunner need to get the class file of the stored object, and consider how ...

Posted on Sat, 04 Apr 2020 15:42:38 -0400 by Beyond Reality

MongoDB learning (II) visual interface

1, Installation visualization interface 1. Mongo booster installation and configuration 1. Download and install Download address: https://nosqlbooster.com/downloads Click Install directly after downloading: Pop up interface after installation: 2. Click create to create the link: 3. Click the Test Connection test link: 4. After the test is O ...

Posted on Sat, 04 Apr 2020 12:43:39 -0400 by madolia

18Python crawler -- crawling Sina News Headlines and saving them in the database

1, Take Sina News ideas 1. Create a sketch project 2. Analysis of static page code of Sina News website 3. Write the corresponding xpath formula 4. Write code 2, Project code Step 1: create a sketch project Create a crawler file scrapy startproject mysqlpjt After entering the project directory scr ...

Posted on Sat, 04 Apr 2020 09:06:32 -0400 by Dave2222