Mongodb

db //show db name

use demo

show databases

show collections

Ctrl + L //clear screen

> db.goo.save({_id:4, x:1, y:true})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.goo.find()
{ "_id" : 4, "x" : 1, "y" : true }
{ "_id" : ObjectId("5b432bcfb1e05bf40d7b9409"), "id" : 4 }
> db.goo.save({_id:4, x:1, y:false})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.goo.find()
{ "_id" : 4, "x" : 1, "y" : false }
{ "_id" : ObjectId("5b432bcfb1e05bf40d7b9409"), "id" : 4 }
> db.goo.save({_id:4, y:false})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.goo.find()
{ "_id" : 4, "y" : false }
{ "_id" : ObjectId("5b432bcfb1e05bf40d7b9409"), "id" : 4 }

> db.goo.insert({_id:4})WriteResult({ "nInserted" : 1 })

> db.goo.find(){ "_id" : 4 }b432bcfb1e05bf40d7b9409"), "id" : 4 }

> db.goo.insert({_id:4})

WriteResult({"nInserted" : 0,"writeError" : {"code" : 11000,"errmsg" : "E11000 duplicate key error collection: demo.goo index: _id_ dup key: { : 4.0 }"}})

> show collectionsgoo 

db.goo.insert({_id:4})
WriteResult({ "nInserted" : 1 })> db.goo.find(){ "_id" : 4 }b432bcfb1e05bf40d7b9409"), "id" : 4 }
>db.goo.insert({_id:4})
WriteResult({"nInserted" : 0,"writeError" : {"code" : 11000,"errmsg" : "E11000 duplicate key error collection: demo.goo index: _id_ dup key: { : 4.0 }"}})
> show collectionsgoo 

save

> db.goo.save({_id:4, x:1, y:true})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.goo.find()
{ "_id" : 4, "x" : 1, "y" : true }
{ "_id" : ObjectId("5b432bcfb1e05bf40d7b9409"), "id" : 4 }
> db.goo.save({_id:4, x:1, y:false})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.goo.find()
{ "_id" : 4, "x" : 1, "y" : false }
{ "_id" : ObjectId("5b432bcfb1e05bf40d7b9409"), "id" : 4 }
> db.goo.save({_id:4, y:false})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.goo.find()
{ "_id" : 4, "y" : false }
{ "_id" : ObjectId("5b432bcfb1e05bf40d7b9409"), "id" : 4 }

Find

> db.goo.find({_id:4})
{ "_id" : 4, "y" : false }
> db.goo.find({y:false})
{ "_id" : 4, "y" : false }
> db.goo.find({_id: {$gt:1, $lt:7}})
{ "_id" : 4, "y" : false }
> db.goo.find({_id:4, y:false})
{ "_id" : 4, "y" : false }

sort

> db.s.insert({y:1})
WriteResult({ "nInserted" : 1 })
> db.s.insert({y:1, x:1})
WriteResult({ "nInserted" : 1 })
> db.s.insert({y:2, x:2})
WriteResult({ "nInserted" : 1 })
> db.s.find()
{ "_id" : ObjectId("5b447030d8cac7b2d5b7a996"), "y" : 1 }
{ "_id" : ObjectId("5b44703ed8cac7b2d5b7a997"), "y" : 1, "x" : 1 }
{ "_id" : ObjectId("5b447053d8cac7b2d5b7a998"), "y" : 2, "x" : 2 }
> db.s.find().sort({y:-1})
{ "_id" : ObjectId("5b447053d8cac7b2d5b7a998"), "y" : 2, "x" : 2 }
{ "_id" : ObjectId("5b447030d8cac7b2d5b7a996"), "y" : 1 }
{ "_id" : ObjectId("5b44703ed8cac7b2d5b7a997"), "y" : 1, "x" : 1 }
> db.s.find().sort({y:1, x:1})
{ "_id" : ObjectId("5b447030d8cac7b2d5b7a996"), "y" : 1 }
{ "_id" : ObjectId("5b44703ed8cac7b2d5b7a997"), "y" : 1, "x" : 1 }
{ "_id" : ObjectId("5b447053d8cac7b2d5b7a998"), "y" : 2, "x" : 2 }
> db.s.find().sort({y:1, x:-1})
{ "_id" : ObjectId("5b44703ed8cac7b2d5b7a997"), "y" : 1, "x" : 1 }
{ "_id" : ObjectId("5b447030d8cac7b2d5b7a996"), "y" : 1 }
{ "_id" : ObjectId("5b447053d8cac7b2d5b7a998"), "y" : 2, "x" : 2 }

Limit

> db.s.find().sort({_id:1}).limit(3)
{ "_id" : ObjectId("5b447030d8cac7b2d5b7a996"), "y" : 1 }
{ "_id" : ObjectId("5b44703ed8cac7b2d5b7a997"), "y" : 1, "x" : 1 }
{ "_id" : ObjectId("5b447053d8cac7b2d5b7a998"), "y" : 2, "x" : 2 }

Backup DB

mongodump --db test --collections s

restore db

mongorestore --db restoredA dump/test