Propagation

Control how a @Transactional() method relates to an already-active transaction with the Propagation enum:

import { Propagation, Transactional } from '@nestjs-transactions/prisma';

@Transactional({ propagation: Propagation.REQUIRES_NEW })
async audit(entry: AuditEntry) {
  /* commits even if the caller rolls back */
}

Mode	Behavior
REQUIRED (default)	Join the current transaction, or start one
REQUIRES_NEW	Always start an independent transaction
NESTED	Savepoint: inner rollback doesn't kill the outer tx
MANDATORY	Throw TransactionNotActiveError if no transaction
NEVER	Throw TransactionAlreadyActiveError if inside one
SUPPORTS	Join if present, run plainly otherwise
NOT_SUPPORTED	Suspend the transaction for this call

NESTED requires sqlFlavor

Propagation.NESTED requires sqlFlavor (savepoints are emulated with raw SQL — not available on MongoDB). Without sqlFlavor, a NESTED call inside a transaction logs a warning and runs as an independent transaction (like REQUIRES_NEW) — it does not join the outer one. REQUIRES_NEW (and the NESTED fallback) take a second pooled connection.