Why PostgreSQL RLS for NHS multi-tenant?

PostgreSQL RLS for NHS: (1) database-level enforcement (bug in application cannot bypass RLS), (2) trust_id RLS policy filters every query automatically, (3) auditable SQL policies -- DTAC assessors review the SQL directly, (4) no code change for new tenant (new Trust = new RLS parameter), (5) DBA can verify isolation independently. ClickMasters NHS RLS: SET app.current_trust_id = $trustId per request. DTAC Domain 2 evidence: RLS SQL policies included in DTAC evidence pack as artefacts.

Is MongoDB suitable for NHS patient data?

MongoDB not recommended for NHS patient data: (1) no native RLS -- application bug = potential patient data leak, (2) no JOIN -- UK GDPR erasure (finding all records for an NHS number across collections) is complex, (3) FHIR R4 is relational -- MongoDB requires application-level join logic, (4) single-document ACID insufficient for payment integrity. MongoDB acceptable for NHS non-patient stores (audit logs, search indices, non-clinical content) with explicit DTAC Domain 2 review.

Postgresql Vs Mysql Vs Mongodb Uk Database 20

PostgreSQL vs MySQL vs MongoDB -- UK Database (2026)

Updated: June 20269 min read

UKGBPComparisonUK GDPRUK Law

Direct Answer

PostgreSQL is ClickMasters default for all UK regulated production workloads: native Row Level Security (NHS patient isolation, FCA multi-tenant), JSONB for FHIR R4 UK Core, full ACID transactions (FCA payments), and the strongest UK GDPR right-to-erasure implementation. MySQL is acceptable for read-heavy non-regulated workloads. MongoDB is right for unstructured document storage only -- not for NHS patient data or FCA regulated financial records. Database choice affects NHS DTAC Domain 2 data isolation, FCA PS21/3 transaction integrity, and UK GDPR right-to-erasure.

Factor	PostgreSQL 16	MySQL 8.x	MongoDB 7.x
NHS patient data isolation (RLS)	BEST -- native Row Level Security per patient/trust	No native RLS -- application-level only	No native RLS -- application-level only
FCA payment ACID transactions	BEST -- full ACID, serialisable isolation	Good -- ACID, InnoDB	Single-document ACID only
UK GDPR erasure (cascade delete)	BEST -- CASCADE + audit trigger, traceable	CASCADE available	Complex -- no JOIN, erasure harder to verify
FHIR R4 JSONB queries	BEST -- JSONB, GIN index for FHIR search	JSON support -- less performant	Native document -- but FHIR needs schema
NHS DTAC Domain 2 RLS	BEST -- SQL policy, auditable by DTAC assessor	Application-level -- harder to audit	Application-level -- harder to audit
Time-series data	Good -- TimescaleDB extension	Less suitable	Good -- time-series support
Full-text search	Good -- tsvector, GIN index	Good -- FULLTEXT index	BEST -- Atlas Search
UK GDPR right to portability	BEST -- COPY TO structured export	Good -- SELECT INTO OUTFILE	Complex -- BSON to JSON
ClickMasters default	All UK regulated (NHS, FCA, GDS)	Read-heavy non-regulated	Unstructured docs, content, catalogues