NoSQL

• Has 4 types
  1. Document (mongodb, couchdb)
     1. Store as json. Can have reference.
     2. Good for
        1. Block, CMS
        2. Big data
        3. Analytics
  2. Key-value (dynamodb, redis).
     1. Good for
        1. Caching
        2. session management
        3. Leader board
  3. Columns (Cassandra, HBase)
     1. have to define the column in advance
     2. Good for
        1. IOT
        2. Inventory Management
        3. Big Data
  4. Graph database (Neo4j, JanusGraph)
     1. Good for
        1. Social network
        2. IAM
        3. Recommendation
• Follows BASE design
• Not suitable for OLAP and OLTP
• Suitable for social media where data is continuosly being updated and eventual consistency is acceptable

[!note]
NoSQL is costly because the database is highly denormalised. Which means different data will be stored at different place in the same time which lead to high resource utilisation and costly