bhavansh/demo-presentation.mongo-db-cheatsheet

Just made it for help

MongoDB Cheat Sheet

MongoDB vs SQL

Start Local MongoDb Server

mongod

Start using mongo db in command line

mongo

Look for help

help

help on db methods

db.help()                    
                

help on collection methods

db.mycoll.help()  

set default number of items to display on shell

DBQuery.shellBatchSize = x   

---

---

Show All Databases

show dbs

Show Current Database

db

Create Or Switch Database

use <dbname>
use acme

• unless you create a collection mongo wont show database

Drop

db.dropDatabase()

Create Collection

db.createCollection(<collection_name>)
db.createCollection('posts')
db.createCollection('multidocs')

Show Collections

show collections

---

---

Insert Row

db.posts.insert({
  title: 'Post One',
  body: 'Body of post one',
  category: 'News',
  tags: ['news', 'events'],
  user: {
    name: 'John Doe',
    status: 'author'
  },
  date: Date()
})

Insert Multiple Rows

db.posts.insertMany([
  {
    title: 'Post Two',
    body: 'Body of post two',
    category: 'Technology',
    date: Date()
  },
  {
    title: 'Post Three',
    body: 'Body of post three',
    category: 'News',
    date: Date()
  },
  {
    title: 'Post Four',
    body: 'Body of post three',
    category: 'Entertainment',
    date: Date()
  }
])

can insert in any form example

• array of objects

db.multidocs.insert({
    title: "Multiple Docs",
    multipleDocs :[{
        title: 'Multiple Docs 1',
        body: 'Body of post two',
        category: 'Hate Java',
        date: Date()
    },
    {
        title: 'Multiple Docs 2',
        body: 'Body of post three',
        category: 'Programming',
        date: Date()
    },
    {
        title: 'Multiple Docs 3',
        body: 'Body of post three',
        category: 'Coding',
        date: Date()
    }],
    Workdone:"YES"
})

• object of object

db.multidocs.insert({
    title: "Multiple Docs",
    multipleDocs :{
        title: 'Multiple Docs 1',
        body: 'Body of post two',
        category: 'Hate Java',
        date: Date()
    },
    Workdone:"YES"
})

• object of objects

db.multidocs.insert({
    title: "Multiple Docs",
    multipleDocs :{
        testdoc:{
            title: 'Multiple Docs 1',
            body: 'Body of post two',
            category: 'Hate Java',
            date: Date()
        },
        testdoc1:{
            title: 'Multiple Docs 1',
            body: 'Body of post two',
            category: 'Hate Java',
            date: Date()
        },
        testdoc1:{
            title: 'Multiple Docs 1',
            body: 'Body of post two',
            category: 'Hate Java',
            date: Date()
        }
    },

    Workdone:"YES"
})

Get All Rows

db.posts.find()

Get All Rows Formatted

db.posts.find().pretty()

Find Rows

db.posts.find({ category: 'News' }).pretty()

Sort Rows

asc

db.posts.find().sort({ title: 1 }).pretty()

desc

db.posts.find().sort({ title: -1 }).pretty()

Count Rows

db.posts.find().count()


db.posts.find({ category: 'News' }).count()

Limit Rows

db.posts.find().limit(2).pretty()

Chaining

• sequence of chaining is immaterial

db.posts.find().limit(2).sort({ title: 1 }).pretty()

db.posts.find().sort({ title: 1 }).limit(2).pretty()

db.posts.find().pretty().sort({ title: 1 }).limit(2)

Foreach

db.posts.find().forEach(function(doc) {
  print("Blog Post: " + doc.title)
})

Find One Row

db.posts.findOne({ category: 'News' })

Find Specific Fields

db.posts.find({ title: 'Post One' }, {
  title: 1,
  author: 1
})

db.posts.find({}, {
  title: 1,
}).pretty()

db.posts.find({}, {
   body: 1
}).pretty()

Update Row

db.posts.update({ title: 'Post Two' },
{
  title: 'Post Two',
  body: 'New body for post 2',
  date: Date()
},
{
  upsert: true
})

Update Specific Field

db.posts.update({ title: 'Post Two' },
{
  $set: {
    body: 'Body for post 2',
    category: 'Technology'
  }
})

Increment Field ($inc)

db.posts.update({ title: 'Post Two' },
{
  $inc: {
    likes: 5
  }
})

Rename Field

db.posts.update({ title: 'Post Two' },
{
  $rename: {
    likes: 'views'
  }
})

Delete Row

db.posts.remove({ title: 'Post Four' })

Sub-Documents

db.posts.update({ title: 'Post One' },
{
  $set: {
    comments: [
      {
        body: 'Comment One',
        user: 'Mary Williams',
        date: Date()
      },
      {
        body: 'Comment Two',
        user: 'Harry White',
        date: Date()
      }
    ]
  }
})

Find By Element in Array ($elemMatch)

db.posts.find({
  comments: {
     $elemMatch: {
       user: 'Mary Williams'
       }
    }
  }
)

Add Index

• adding index of title

db.posts.createIndex({ title: 'text' })

Text Search

db.posts.find({
  $text: {
    $search: "\"Post O\""
    }
}).pretty()

Greater & Less Than

db.posts.find({ views: { $gt: 2 } })
db.posts.find({ views: { $gte: 7 } })
db.posts.find({ views: { $lt: 7 } })
db.posts.find({ views: { $lte: 7 } })