//Slide 17 – first connect to server and select a database to use
//get connection by using string from Atlas
mongo "mongodb+srv://cluster0-rq8e6.mongodb.net/cs61” --username cs61 
show dbs
db //test
//switch to cs61 database
use cs61

//Slide 18 – dropDatabase deletes a database
//drop cs61
db.dropDatabase()
//show db is still cs61 (even though dropped)
db //returns cs61

//Slide 19 – createCollection makes a collection, like CREATE TABLE
//create a new collection called Restaurants
db.createCollection("Restaurants")
//show all collections in database
show collections

//Slide 20 – insert documents into a collection with insert, list with find
//insert restaurant into Restaurants collection
db.Restaurants.insert({name:"Tim's Tasty Treats",boro:"Manhattan"})
//find restaurants – like SELECT
db.Restaurants.find()
db.Restaurants.find().pretty()
//note _id not inserted, so Mongo created one, if had provided _id field, Mongo would use that instead of creating one

//Slide 21- insert several documents at the same time by using a JSON array
//insert several restaurants into Restaurants collection
db.Restaurants.insert([{name:"Tim's Untasty Treats",boro:"Queens"},{name: "Brooklyn's Best Restaurant",boro:"Brooklyn"},{name:"Bronx diner",boro:"Bronx"}])
//show all restaurants
db.Restaurants.find().pretty()
//can also use insertOne and insertMany

//Slide 22 – find returns documents matching the provided criteria
//find restaurants in Manhattan
db.Restaurants.find({boro:"Manhattan"}).pretty() //only Tim’s Tasty Treats
//can also use $or (must put conditions in array)
db.Restaurants.find({$or: [{boro:"Manhattan"},{boro:"Queens"}]}).pretty()
Slide 23 – find can also project fields and limit the number of documents returned
//return only the name of restaurants
db.Restaurants.find({},{"name":1}).pretty() //get _id by default also, turn it off
db.Restaurants.find({},{"name":1,_id:0}).pretty() //no _id field
//add limit
db.Restaurants.find({}).limit(2) //only two returned

//Slide 24 – add sort to sort the results
//use 1 to sort ascending, -1 to sort descending
db.Restaurants.find({}).sort({boro:1}) //ascending by boro
db.Restaurants.find({}).sort({boro:-1}) //descending by boro
db.Restaurants.find({}).sort(name:1}.limit(2) //only first two returned

//Slide 25 – update can add new fields or update existing fields
//find restaurants
db.Restaurants.find({}) //get _id for Tim’s Tasty Treats
//add score field to Tim’s Tasty Treats – get _id from find!
db.Restaurants.update({_id:ObjectId("5ebfe42a6ead6c5a3b84c554")},{$set:{score:5}})
//score field created on Tim’s
//update score field to Tim’s Tasty Treats to have score of 6
db.Restaurants.update({_id:ObjectId("5ebfe42a6ead6c5a3b84c554")},{$set:{score:6}})

//Slide 26 – use remove to delete documents
//add score to Bronx Diner – get _id from find!
db.Restaurants.update({_id:ObjectId("5ebfe8c46ead6c5a3b84c558")},{$set:{score:12}})
//remove all restaurants with score > 6
db.Restaurants.remove({score: {$gt: 6}}) //Bronx Diner removed
//use db.Restaurants.remove({}) to TRUNCATE

//Slide 27 – Use createIndex to add an index on a field for faster lookup like a RDBMS
//use getIndexes to see existing indexes
db.Restaurants.getIndexes()
//add index on boro
db.Restaurants.createIndex({boro:1}) // 1 means ascending
//drop indexes
db.Restaurants.dropIndex({boro:1})

/*
Slide 28 - Practice
1.	Create a collection to hold data about Students where each Student has:
•	Name
•	Year
*/
db.Students.createCollection(“Students”)

/*
2.	Insert three students
•	Alice 20
•	Bob 21
•	Charlie 22
*/
db.Students.insert([{name:"Alice",year:20},{name:"Bob",year:21},{name:"Charlie",year:22}])

//3.	Add GPA attribute to Alice, give her a 3.5 
db.Students.update({_id:ObjectId("5ec5146400766dcb02610ddb")},{$set:{GPA:3.4}})

//4.	Find Students where year > 20
db.Students.find({year: {$gt:20}})