🗄️ NoSQL Databases for Data Engineers
Explore NoSQL database types including document stores, key-value stores, column-family databases, and graph databases.
Level:
Intermediate
Tools:
MongoDB
Redis
Cassandra
Neo4j
DynamoDB
Skills You'll Learn:
Document stores
Key-value stores
Column-family stores
Graph databases
CAP theorem
When to use NoSQL
Step 1: NoSQL Fundamentals
- 1Understand the motivation behind NoSQL databases and their history
- 2Learn the four main categories of NoSQL databases: document, key-value, column-family, and graph
- 3Compare NoSQL schema-on-read with relational schema-on-write approaches
- 4Understand denormalization and why NoSQL databases embrace data duplication
- 5Identify real-world use cases where NoSQL outperforms relational databases
Step 2: Document Databases (MongoDB)
- 1Install MongoDB and connect using the shell or MongoDB Compass
- 2Create databases, collections, and insert documents with nested structures
- 3Query documents using find, filters, projections, and the aggregation pipeline
- 4Design document schemas for embedded vs referenced relationships
- 5Use indexes to optimize read performance on common query patterns
Step 3: Key-Value Stores (Redis)
- 1Install Redis and connect using redis-cli
- 2Work with core data types: strings, hashes, lists, sets, and sorted sets
- 3Implement caching patterns using TTL (time-to-live) expiration
- 4Use Redis pub/sub for simple real-time messaging between services
- 5Understand Redis persistence options (RDB snapshots vs AOF) and their trade-offs
Step 4: Column-Family Stores (Cassandra)
- 1Understand Cassandra's distributed architecture and the concept of a ring topology
- 2Define keyspaces and tables using CQL (Cassandra Query Language)
- 3Design partition keys and clustering keys for efficient data distribution
- 4Model data around query patterns instead of entity relationships
- 5Understand replication strategies and tunable consistency levels
Step 5: Graph Databases (Neo4j)
- 1Understand the property graph model: nodes, relationships, and properties
- 2Install Neo4j and explore the browser interface
- 3Write Cypher queries to create, read, update, and delete graph data
- 4Traverse relationships using variable-length path queries
- 5Identify use cases where graph databases excel: recommendations, fraud detection, and social networks
Step 6: CAP Theorem and Consistency Models
- 1Understand the CAP theorem: Consistency, Availability, and Partition tolerance
- 2Learn the difference between strong consistency, eventual consistency, and causal consistency
- 3Map popular NoSQL databases to their CAP trade-offs (CP vs AP)
- 4Understand quorum reads and writes and how they tune consistency
Step 7: Choosing the Right Database
- 1Evaluate access patterns: read-heavy, write-heavy, or mixed workloads
- 2Consider data shape: nested documents, flat key-value, wide rows, or connected graphs
- 3Assess scalability requirements: vertical vs horizontal scaling
- 4Compare managed cloud offerings: DynamoDB, Cosmos DB, Cloud Bigtable, and Amazon Neptune
- 5Practice choosing the right database for three different real-world scenarios
Recommended Resources
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