Mongo basics drills.md

Get all

db.restaurants.find()

Limit and sort

Find the command that makes the first 10 restaurants appear when db.restaurants is alphabetically sorted by the name property.

db.restaurants.find().sort({name:1}).limit(10)

Get by _id

Retrieve a single restaurant by _id from the restaurants collection. This means you'll first need to get the _id for one of the restaurants imported into the database.

var id = db.restaurants.findOne()._id; db.restaurants.find({_id:id})

Get by value

Write a command that gets all restaurants from the borough of "Queens".

db.restaurants.find({borough:"Queens"})

Count

Write a command that gives the number of documents in db.restaurants.

db.restaurants.find().count()

Count by nested value

Write a command that gives the number of restaurants whose zip code value is '11206'. Note that this property is at document.address.zipcode, so you'll need to use dot notation to query on the nested zip code property.

db.restaurants.find({'address.zipcode':'11206'}).count()

Delete by id

Write a command that deletes a document from db.restaurants. This means you'll first need to get the _id for one of the restaurants imported into the database.

var id=db.restaurants.findOne()._id; db.restaurants.remove({_id:id});

Update a single document

Write a command that sets the name property of a document with a specific _id to 'Bizz Bar Bang'. Make sure that you're not replacing the existing document, but instead updating only the name property.

db.restaurants.updateOne({_id: id},{$set:{name:"Bizz Bar Bang"}})

Update many documents

Uh oh, two zip codes are being merged! The '10035' zip code is being retired, and addresses with '10035' will now fall under the '10036' zip code. Write a command that updates values accordingly.

db.restaurants.updateMany({'address.zipcode':'10035'},{$set:{'address.zipcode':'10036'}})