Why does NHS DTAC recommend PostgreSQL over MySQL?

NHS DTAC does not explicitly name PostgreSQL — but PostgreSQL's native Row Level Security (RLS) provides the strongest DTAC Domain 2 data protection for multi-tenant NHS applications. RLS: a database-level control that ensures a query from one NHS Trust cannot return data from another (even if application code has a bug). MySQL has no native RLS — data isolation must be implemented in application code (a bug could expose cross-tenant data). For NHS ICB population health analytics (multiple NHS Trust data in one database): PostgreSQL RLS isolates each Trust's patient data at the database level. ClickMasters implements PostgreSQL RLS for all NHS multi-tenant applications — DTAC Domain 2 evidence includes RLS policy definition.

When should UK projects use MongoDB instead of PostgreSQL?

MongoDB over PostgreSQL when: (1) genuinely document-native data (content management system — each page has a different schema, no fixed columns), (2) IoT sensor data at high write volume (time-series writes at 10,000/second — PostgreSQL handles this but MongoDB TimeSeries Collections are optimised), (3) full-text search is the primary query pattern (MongoDB Atlas Search is better than PostgreSQL FTS for complex search requirements), (4) team has deep MongoDB expertise (existing Atlas infrastructure, established Mongoose patterns). MongoDB is not appropriate for: NHS patient records (no native RLS), FCA trading data (ACID transaction requirements make document databases a risk), or any regulated UK application where database-level access controls are part of the compliance evidence.

Postgresql Vs Mysql Vs Mongodb Uk 2026

PostgreSQL vs MySQL vs MongoDB — UK Database Choice (2026)

Updated: March 20269 min read

🇬🇧 UK💷 GBP📊 Comparison🔒 UK GDPR⚖️ UK Law

Direct Answer

PostgreSQL is ClickMasters' default for all UK regulated applications: best JSON support, native FHIR R4 data storage (JSONB), Row Level Security for multi-tenant UK GDPR data isolation, mature UK NHS/FCA audit trail patterns, and AWS RDS + Neon.tech ecosystem. MongoDB is right for document-native workloads (content management, IoT sensor data, user-generated content). MySQL/Aurora MySQL is right when the team has deep existing MySQL expertise and no regulatory driver for PostgreSQL. UK database choice affects NHS DTAC Domain 2 data protection controls, FCA audit trail requirements, and GDPR Row Level Security implementation.

Factor	PostgreSQL	MySQL / Aurora MySQL	MongoDB
UK GDPR Row Level Security	✅ Native RLS — multi-tenant isolation	No native RLS — application-layer only	No native RLS
NHS FHIR R4 (JSONB storage)	✅ JSONB — queryable JSON (FHIR resources stored natively)	JSON support — less queryable	✅ Native document storage — good for FHIR
FCA audit trail (immutable)	✅ Triggers + temporal tables — well-established pattern	Triggers available	Change Streams — available
Prisma / Drizzle ORM	✅ Best support — most features	Good support	Good support
AWS managed offering	RDS PostgreSQL + Aurora PostgreSQL	✅ RDS MySQL + Aurora MySQL	MongoDB Atlas (not AWS-native)
Neon.tech (serverless)	✅ Neon is PostgreSQL — free tier, branching	Not available	Not available
Full-text search	PostgreSQL FTS (tsvector) — adequate	Limited	✅ Atlas Search — excellent
Transactions (ACID)	✅ Full ACID — multi-table	✅ Full ACID (InnoDB)	Multi-document transactions — available
ClickMasters default	✅ All NHS, FCA, GDS, and SaaS UK projects	Legacy MySQL migrations, WordPress	IoT data, CMS, document-heavy apps