#Data Management Patterns

Patterns for managing data in cloud applications.

#Key Patterns

#Cache-Aside Pattern

diagram

Application ──▶ Cache?  ──▶ Yes ──▶ Return cached
                  │
                  No
                  │
                  ▼
              Database ──▶ Update cache ──▶ Return

#CQRS (Command Query Responsibility Segregation)

diagram

Commands ──▶ Write Model ──▶ Database
                              │
                              ▼
Queries  ◀── Read Model  ◀── Events

#Event Sourcing

Store all changes as events:

Event 1: AccountCreated { id: 123 }
Event 2: MoneyDeposited { id: 123, amount: 100 }
Event 3: MoneyWithdrawn { id: 123, amount: 50 }

#Sharding

Strategy	Description
Hash-based	Hash of key determines shard
Range-based	Key ranges per shard
Geographic	Location-based

#Database Selection

Use Case	Database Type
Transactions	PostgreSQL, MySQL
Documents	MongoDB
Key-Value	Redis, DynamoDB
Time Series	InfluxDB, TimescaleDB
Graph	Neo4j

[!TIP] Pro Tip: Choose databases based on access patterns, not popularity!