# PostgreSQL Migration Documentation

## Overview

Successfully migrated the livedash-node application from SQLite to PostgreSQL using Neon as the database provider. This migration provides better scalability, performance, and production-readiness.

## Migration Summary

### What Was Changed

1.  **Database Provider**: Changed from SQLite to PostgreSQL in `prisma/schema.prisma`
2.  **Environment Configuration**: Updated to use environment-based database URL selection
3.  **Test Setup**: Configured separate test database using `DATABASE_URL_TEST`
4.  **Migration History**: Reset and created fresh PostgreSQL migrations

### Database Configuration

#### Production/Development

- **Provider**: PostgreSQL (Neon)
- **Environment Variable**: `DATABASE_URL`
- **Connection**: Neon PostgreSQL cluster

#### Testing

- **Provider**: PostgreSQL (Neon - separate database)
- **Environment Variable**: `DATABASE_URL_TEST`
- **Test Setup**: Automatically switches to test database during test runs

### Files Modified

1.  **`prisma/schema.prisma`**

- Changed provider from `sqlite` to `postgresql`
- Updated URL to use `env("DATABASE_URL")`

2.  **`tests/setup.ts`**

- Added logic to use `DATABASE_URL_TEST` when available
- Ensures test isolation with separate database

3.  **`.env`** (created)

- Contains `DATABASE_URL` for Prisma CLI operations

4.  **`.env.local`** (existing)

- Contains both `DATABASE_URL` and `DATABASE_URL_TEST`

### Database Schema

All existing models and relationships were preserved:

- **Company**: Multi-tenant root entity
- **User**: Authentication and authorization
- **Session**: Processed session data
- **SessionImport**: Raw CSV import data
- **Message**: Individual conversation messages
- **Question**: Normalized question storage
- **SessionQuestion**: Session-question relationships
- **AIProcessingRequest**: AI cost tracking

### Migration Process

1.  **Schema Update**: Changed provider to PostgreSQL
2.  **Migration Reset**: Removed SQLite migration history
3.  **Fresh Migration**: Created new PostgreSQL migration
4.  **Client Generation**: Generated new Prisma client for PostgreSQL
5.  **Database Seeding**: Applied initial seed data
6.  **Testing**: Verified all functionality works with PostgreSQL

### Benefits Achieved

✅ **Production-Ready**: PostgreSQL is enterprise-grade and scalable  
✅ **Better Performance**: Superior query performance and optimization  
✅ **Advanced Features**: Full JSON support, arrays, advanced indexing  
✅ **Test Isolation**: Separate test database prevents data conflicts  
✅ **Consistency**: Same database engine across all environments  
✅ **Cloud-Native**: Neon provides managed PostgreSQL with excellent DX

### Environment Variables

```env
# Production/Development Database
DATABASE_URL="postgresql://user:pass@host/database?sslmode=require"

# Test Database (separate Neon database)
DATABASE_URL_TEST="postgresql://user:pass@test-host/test-database?sslmode=require"
```

### Test Configuration

Tests automatically use the test database when `DATABASE_URL_TEST` is set:

```typescript
// In tests/setup.ts
if (process.env.DATABASE_URL_TEST) {
  process.env.DATABASE_URL = process.env.DATABASE_URL_TEST;
}
```

### Verification

All tests pass successfully:

- ✅ Environment configuration tests
- ✅ Transcript fetcher tests
- ✅ Database connection tests
- ✅ Schema validation tests
- ✅ CRUD operation tests

### Next Steps

1.  **Data Import**: Import production data if needed
2.  **Performance Monitoring**: Monitor query performance in production
3.  **Backup Strategy**: Configure automated backups via Neon
4.  **Connection Pooling**: Consider connection pooling for high-traffic scenarios

### Rollback Plan

If rollback is needed:

1.  Revert `prisma/schema.prisma` to SQLite configuration
2.  Restore SQLite migration files from git history
3.  Update environment variables
4.  Run `prisma migrate reset` and `prisma generate`

## Conclusion

The PostgreSQL migration was successful and provides a solid foundation for production deployment. The application now benefits from PostgreSQL's advanced features while maintaining full test isolation and development workflow compatibility.