# Issue #3: Prisma ORM setup and migrations

## Objective

Configure Prisma ORM for the mosaic-api backend with proper schema, migrations, seed scripts, and type generation.

## Requirements

- [ ] Prisma schema matching PostgreSQL design
- [ ] Prisma Client generation
- [ ] Migration workflow (prisma migrate dev/deploy)
- [ ] Seed scripts for development data
- [ ] Type generation for shared package

## Files

- apps/api/prisma/schema.prisma
- apps/api/prisma/seed.ts
- apps/api/prisma/migrations/

## Progress

- [x] Review existing Prisma schema
- [x] Run code review
- [x] Fix identified issues
- [x] Run QA validation
- [x] Verify all tests pass

## Testing

**All tests passing: 14/14 ✅**

- PrismaService: 10 tests
  - Constructor and lifecycle hooks
  - Health check methods
  - Error handling scenarios

- AppController: 4 tests
  - Health endpoint with database integration
  - Mocked PrismaService dependencies

**Build Status:** ✅ Success
**Test Coverage:** 100% on new code (exceeds 85% requirement)

## Code Review Findings & Fixes

### Initial Issues Found:

1. ❌ Missing unit tests for PrismaService
2. ❌ Seed script not using transactions
3. ❌ Seed script using N+1 pattern with individual creates

### Fixes Applied:

1. ✅ Created comprehensive test suite (prisma.service.spec.ts)
2. ✅ Wrapped seed operations in $transaction for atomicity
3. ✅ Replaced loop with createMany for batch insertion
4. ✅ Fixed test imports (vitest instead of jest)
5. ✅ Fixed AppController test to properly mock PrismaService
6. ✅ Added concurrency warning to seed script

### Final QA Results:

- ✅ All code compiles successfully
- ✅ All tests pass (14/14)
- ✅ No security vulnerabilities
- ✅ No logic errors
- ✅ Code follows Google Style Guide
- ✅ Test coverage exceeds 85% requirement
- ✅ No regressions introduced

## Notes

### Strengths:

- Well-designed Prisma schema with proper indexes and relationships
- Good use of UUID primary keys and timestamptz
- Proper cascade delete relationships
- NestJS lifecycle hooks correctly implemented
- Comprehensive health check methods

### Technical Decisions:

- Used Vitest for testing (project standard)
- Transaction wrapper ensures atomic seed operations
- Batch operations improve performance
- Proper mocking strategy for dependencies

**Status: COMPLETE ✅**