AWS ‐ Database Services ‐ RDS | DocumentDB | DynamoDB | ElastiCache | Keyspaces | Neptune | Quantum Ledger | Aurora | Redshift | Timestream

Relational Database

• Data is stored in a relationship structure
• Data stored in tables as Rows and Columns (property information about the row)
• Use SQL to access/query the data

Data Integrity

• Completeness of the data (you can define constraints such as firstname, lastname canot be null, so the consumer of the data will have complete information)
• Consistency - consumer can rely on the data
• Accuracy - defining data model, relationship properly

Database Transactions

• Collection of SQL statements processed in sequence
• All or None functionality - If all these statement executions are succeed then the changes are applied to the database, if any one statement is fail then no changes are applied.
• Db Transactions must be ACID
  • Atomic - entire execution of statements should be successful, not just part of it
  • Consistent - data written in db must adhere to all the rules and constraints defined
  • Isolation - transactions independent, doesnt rely on any other trnx for it to succeed
  • Durable - all the changes made to db are permanent

Amazon Relational Databases supported

• Amazon Aurora
• MariaDb
• MS SQL Server
• MySQL
• Oracle
• PostgreSQL

NoSQL (Non-Relational) Databases

• To support varied data model (unstructured schema)

• Used to store large amount of data - with less constraints

• Supports Flexible data models

• Provides Low latency - because less validations on the constraints and rules compared to relational database

• Scalability & Performance - less processing and validations, efficient to compress and store data

• Flexibility - stores different types of data

Types of NoSQL Database

• Key-Value
• DocumentDb
• Graph db
• Search db
• In-Memory db

Comparison between sql and nosql database

Database Consistency Models