Base Notes
table → collections
row → documents
column → fields
Base Commands
start mongodb → mongo
show dbs → to show data bases
use newdb → if db is not present then create it otherwise use it
db → give active database
Create
insertOne()
db.collectionname.insertOne({name:”ReactJS”,type:”frontend”,videos:80,active:true}) → it create colleection of collectionname and create document
insertMany()
db.collectionname.insertMany([{ name:”ReactJS”,type:”frontend”,videos:80,active:true},{name:”ReactJS”,type:”frontend”,videos:80,active:true}])show collections → gives all collections in dbdb.collectionname.find() → gives all documents of the collectionname
db.collectionname.find().pretty() → give documents of collectionname in a good format
Read
find()
db.collection.find({queary,projection}) → for read
db.collection.find({name:”physics”},{_id:0,name:1}) → it will print name of having name as physics
limit()
db.collection.find({name:”physics”},{_id:0,name:1}).limit(2)-> it will only print first 2
findOne() → gives on document
db.collection.findOne({name:”physics”},{_id:0,name:1})
skip(1)→ it will give from second one
db.collection.find({name:”physics”},{_id:0,name:1}).limit(2).skip(1)
UPDATE
updateOne() ⇒ db.collection.updateOne(,)
db.cone.updateOne({name:"Physics"},{$set:{value:300}}) → update value by 300 of doc having name Physics
updateMany() ⇒ db.collection.updateMany(,)
db.cone.updateMany({name:"Physics"},{$set:{value:300}}) → update value by 300 of docs having name Physics
Delete
deleteMany(criteria)
db.cone.deleteMany({name:"Physics"}) → delete doc having name as Physics
db.cone.deleteMany({}) → delete all docs
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