Review old stuff: mongoDB

blockquote

Recently, I revisited old skills, extending to MongoDB. After reinstalling MongoDB, I felt that the website architecture had significantly changed compared to what I saw the last time I created a sample. My old sample project was a record of main characters from the Japanese anime "Demon Slayer." In just four years, from March 2020 to now, there has been a significant change in the website structure, indicating considerable improvements in MongoDB's functionality.

Resource

Some content has been spread out, but I find this arrangement clearer. Below are the resources I briefly looked up:

community version: https://www.mongodb.com/try/download/community-edition

MongoDB shell: https://www.mongodb.com/try/download/shell

Database tools: https://www.mongodb.com/try/download/bi-connector  ( dump, restore, import, export) 

NodeJS reference (developer): https://www.mongodb.com/docs/drivers/node/current/quick-reference/

mongosh manual: https://www.mongodb.com/docs/manual/reference/method/

mongoimport

mongoimport -d dest-db --jsonArray datafile.json

mongosh

Interesting topics covered during the review include:  
Count record:

db.collection.count()

Select some fields and remove _id:

db.collection.find({}, { field_name1: 1,  field_name2: 1,  _id:0 } ) 

Select and/or: (operator)

db.collection.find({field_name1:value1, { $or: [ { field_name2: { $lt: 20 } }, { field_name2: value2 } ] })

Use cursor:

var cursor1 = db.collection.find()
cursor1.next()
cursor1.close()

ExpressJS (NodeJs/JavaScript) 

Doc: 
mozilla: https://developer.mozilla.org/en-US/docs/Learn/Server-side/Express_Nodejs

npm install express
npm install express-generator -g
express project_name --view=jade
cd peoject_name
npm install
SET DEBUG=express-locallibrary-tutorial:* & npm start

# --view=dust|ejs|hbs|hjs|jade|pug|twig|vash 
# npm WARN deprecated mkdirp@0.5.1: ... https://stackoverflow.com/questions/62859986/error-when-install-express-generator-using-npm

mongoose

Docs: 
mongoose: https://mongoosejs.com/docs/index.html
npm: https://www.npmjs.com/package/mongoose

Install:

npm install mongoose --save 

In VS code, the following will be created: 

package.json 
package_lock.json
node_modules