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CRUD operations

This is a cheat sheet of basic MongoDB CRUD operations.

We are going to use a collection which has the following form:

{
    "country" : "United Kindgom",
    "city" : "London",
    "population" : "62,348,447",
    "languages" : [
                  "English",
                  "Urdu",
                  "Arabic"
                  ]
}

{
    "country":"United States",
    "city" : "Washington",
    "population" : "310,232,863",
    "languages" : [
                  "English",
                  "Spanish",
                  "Arabic"
                  ]
 }

Create

Create a database called world:

use world

Create a collection called population in the world database:

use world
db.createCollection("population")

Insert a document into the collection population:

db.population.insert({
    "country":"United Kindgom",
    "city" : "London",
    "population" : "62,348,447",
    "languages" : [  
    "English",
    "Urdu",
    "Arabic"]
})

Read

Find all documents in the database:

db.collection.find()

Output:

{"_id" : ObjectId("52f10dd59ce0b0c798ef4f33"), "country" : "United Kindgom", "city" : "London", "population" : "62,348,447", "languages" : ["English","Urdu","Arabic"]}

Make the output readable:

db.collection.find().pretty()

Output:

{
    "_id" : ObjectId("52f10dd59ce0b0c798ef4f33"),
    "country" : "United Kindgom",
    "city" : "London",
    "population" : "62,348,447",
    "languages" : [
                  "English",
                  "Urdu",
                  "Arabic"
                  ]
}

 

Find all documents where the city is London:

db.population.find({ city : "London" }).pretty()

Output:

{
    "country" : "United Kindgom",
    "city" : "London",
    "population" : "62,348,447",
    "languages" : [
                  "English",
                  "Urdu",
                  "Arabic"
                  ]
}

Find all documents where the languages is Spanish:

db.population.find( { languages: { $in: [ "Spanish" ] } } )

Output:

{
    "country":"United States",
    "city" : "Washington",
    "population" : "310,232,863",
    "languages" : [
                  "English",
                  "Spanish",
                  "Arabic"
                  ]
 }

 

 

 

 

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