Category
sql
4 articles across 3 sub-topics
Sharding Approaches in SQL and NoSQL: Range, Hash, and Directory-Based Strategies Compared
TLDR: Sharding splits your database across multiple physical nodes so no single machine carries all the data or absorbs all the writes. The strategy you choose — range, hash, consistent hashing, or directory — determines whether range queries stay ch...
Partitioning Approaches in SQL and NoSQL: Horizontal, Vertical, Range, Hash, and List Partitioning
TLDR: Partitioning splits one logical table into smaller physical pieces called partitions. The database planner skips irrelevant partitions entirely — turning a 30-second full-table scan into a 200ms single-partition read. Range partitioning is best...
Isolation Levels in Databases: Read Committed, Repeatable Read, Snapshot, and Serializable Explained
TLDR: Isolation levels control which concurrency anomalies a transaction can see. Read Committed (PostgreSQL and Oracle's default) prevents dirty reads but still silently allows non-repeatable reads, write skew, and lost updates. Repeatable Read adds...
Database Anomalies: How SQL and NoSQL Handle Dirty Reads, Phantom Reads, and Write Skew
TLDR: Database anomalies are the predictable side-effects of concurrent transactions — dirty reads, phantom reads, write skew, and lost updates. SQL databases use MVCC and isolation levels to prevent them; PostgreSQL's Serializable Snapshot Isolation...