NoSQL

Internal

• System Design
• Databases

Overview

The NoSQL databases are grouped in four categories:

1. document stores
2. key-value stores
3. graph stores
4. column stores

NoSQL Databases

Document Databases

Google Bigtable introduced a data model allowing rows to be added with any set of columns. The columns do not need to be predefined. The lack of predefined schema makes these databases attractive for applications where the attributes of objects are not known in advance or change frequently.

• Google Bigtable
• Cassandra
• HBase
• Hypertable

Document databases are conceptually similar to Google Bigtable database. They have a related data model, where a Bigtable row with its arbitrary number of columns/attributes corresponds to a document. The document is a tree of objects containing attribute values and lists, often with a mapping to JSON or XML. Unlike dumping JSON in a relational database, the document databases can work with the structure of the documents, they can extract, index, aggregate and filter based on attribute values in these documents.

• CouchDB
• MongoDB
• Voldemort

Graph Databases

• CouchDB
• Neo4j
• Amazon DynamoDB

Organizatorium

• NoSQL discussion: https://bigdata-ir.com/wp-content/uploads/2017/04/NoSQL-Distilled.pdf NoSQL Distilled by Sadalage, Fowler. (Learning/Systems Design)
• Should you go Beyond Relational Databases? https://blog.teamtreehouse.com/should-you-go-beyond-relational-databases
• Lack of predefined schema.