Bazy dannyh: SQL vs NoSQL vybor

Vybor mezhdu SQL (relyatsionnye) i NoSQL (nerelyatsionnye) bazami dannyh kritichen dlya arhitektury.

SQL (Relational)

Strukturirovannye dannye, ACID, SQL yazyk.

Populyarnye:

• PostgreSQL: Rasshiryaemost, JSONB, polnotekstovyy poisk
• MySQL/MariaDB: Prostota, shirokaya podderzhka

Kogda ispolzovat:

• Slozhnye svyazi mezhdu dannymi
• Tranzaktsii i konsistentnost
• Otchyoty i analitika

NoSQL

Gibkaya shema, gorizontalnoe masshtabirovanie.

Tipy:

• Document (MongoDB): JSON-podobnye dokumenty
• Key-Value (Redis): Bystryy dostup po klyuchu
• Column (Cassandra): Masshtabiruemye kolonki
• Graph (Neo4j): Slozhnye svyazi

Kogda ispolzovat:

• Bystro menyayuschiesya trebovaniya
• Ogromnye obyomy dannyh
• Georaspredelyonnye sistemy

CAP Teorema

Nevozmozhno odnovremenno obespechit Consistency, Availability, Partition tolerance. Prihoditsya vybirat dva iz tryoh.

Poliglot persistence

Sovremennye prilozheniya ispolzuyut neskolko BD:

• PostgreSQL dlya osnovnyh dannyh
• Redis dlya kesha
• Elasticsearch dlya poiska
• MongoDB dlya logov