Databases

SQL

NoSQL

Types

Example

PostgreSQL:
Install, Commands(Create/Connect/List/Delete database, tables. Insert data)
Stored procedures, Function, Extensions (pg_trgm), pgmq(Postgres Inbuilt MessageQueue), PgBouncer(Connection Pooler)
CockroachDB, MariaDB, MySQL, Amazon RDS, Amazon Aurora

Database	Date model	Storage Method	Example
Document	json, xml	B-Trees, B+ Trees	Mongodb, couchdb
Wide Column		LSM Trees	Cassandra, ScyllaDB, HBase, Google Bigtable
Columnar / Column Oriented			Apache Kudu, MonetDB, InfiniDB
Key-Value		HashMap(RAM), LSM Trees(Disk)	Redis, Amazon DynamoDB
Time-Series	Time-stamped metrics and events	LSM Trees, Columnar Compression	InfluxDB, TimescaleDB, QuestDB
Graph	Graphs	Index-Free Adjacency	Neo4j, Amazon Neptune
Vector	Embeddings	HNSW, IVF (Inverted File Index)	Pinecone, Milvus, Qdrant, Weaviate

Issues

SQL Database Issues

DB Scaling: Replication, Federation, Sharding/Partitioning
DB Schema

Terms:
ACID(Atomicity, Consistency, Isolation, Durability)
Indexing(Forward, Reverse)
Isolation(Read Committed, Snapshot Isolation)
JOIN(Left, Right, Inner, Full, Cross)
Transaction(Dirty Read, Dirty Write, Read Skew, Write Skew, 2PC(Two Phase Commit))