MongoDB

MongoBD is NoSQL document database. MongoDB is single master model and has a number of slave nodes. If master goes down, one of the slaves will be master. This is done automatically but it will tale 10-30 seconds.

Term	Description	Example
Databse	Contains collections	airbnb.db
Collections	A collection is a group of documents. In RDBMS, this is a TABLE.	User, Booking, Room
Documents	Contains basic unit of information.	{ firstName: "Kei", lastName: "Oka" }
Namespace	Concatenation of the database name and collection name.	school.student

https://www.youtube.com/watch?v=UFVFIKduXpo

Indexes

By default MongoDB creates the _id property which is index. Without indexes, MongoDB must scan collection (called collection scan). If mongoDB can use index, querying is done efficiently. Array filed puts indexes on each value of itself.

Covered query

Journaling

Sharding

Sharding is a method for distributing data across multiple machines. MongoDB uses sharding to support deployments with very large data sets and high throughput operations.

https://www.youtube.com/watch?v=W3HhqMvwZP8

https://www.youtube.com/watch?v=UFVFIKduXpo&t=521s