# Database Integrity Fix Report (TOPIQ Phase 1 — Step 4)

**Environment**: Node.js v25.9.0 | MySQL 9.7.1 | Database: `topiq`  
**Execution Date**: 2026-10-09  
**Status**: Completed and Fully Verified  

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## 1. Executive Summary

This report documents the implementation and verification of the three integrity fixes identified during the migration verification review. All changes were applied via a non-destructive forward migration and code refinements to the migration runner.

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## 2. Implemented Fixes

### Fix 1: Enforce Student–Coordinator–ASM Consistency
- **Problem**: `student_profiles` stored `coordinator_id` and `asm_id` independently. The database permitted a Student to have an `asm_id` different from their Coordinator's associated `asm_id`.
- **Migration File**: `migrations/003_enforce_hierarchy_composite_fk.sql`
- **Constraints Added**:
  1. `UNIQUE KEY uq_coordinator_asm (user_id, asm_id)` on `coordinator_profiles`.
  2. `CONSTRAINT fk_student_coordinator_asm FOREIGN KEY (coordinator_id, asm_id) REFERENCES coordinator_profiles (user_id, asm_id) ON DELETE RESTRICT` on `student_profiles`.
- **Preflight Validation**:
  - Implemented pre-migration hook in `scripts/migrate.js`.
  - Queries for existing records where `student_profiles.asm_id != coordinator_profiles.asm_id` or where Coordinator references are missing.
  - If violations exist, reports count without exposing personal records and halts safely with exit code 1 without modifying or recording the migration.

### Fix 2: Add Missing Student Class Foreign Key
- **Problem**: `student_profiles.class_id` was unconstrained, risking orphaned references if classes were deleted or non-existent IDs entered.
- **Migration File**: `migrations/003_enforce_hierarchy_composite_fk.sql`
- **Constraints Added**:
  - `CONSTRAINT fk_student_class FOREIGN KEY (class_id) REFERENCES classes (id) ON DELETE SET NULL` on `student_profiles`.
- **Policy**:
  - `class_id` is nullable.
  - `ON DELETE SET NULL` preserves student active status while disassociating invalid/deleted class records.
- **Preflight Validation**:
  - Preflight check in `scripts/migrate.js` validates that any existing non-null `class_id` values reference valid rows in `classes`.

### Fix 3: Correct Migration Runner Exit Handling
- **Problem**: `scripts/migrate.js` previously contained `process.exit(0)` inside the `finally` block, which risked masking errors.
- **File Modified**: `scripts/migrate.js` (and `scripts/migration-status.js`)
- **Improvements**:
  - Established explicit `let exitCode = 0;` tracking. Any error sets `exitCode = 1;`.
  - Removed premature `process.exit(0)` from the `finally` block.
  - Ensured `RELEASE_LOCK('topiq_migration_lock')` is executed on the dedicated connection that acquired it.
  - Guaranteed `connection.release()` and `await pool.end()` are called before exiting.
  - Cleaned SQL single-line comments prior to splitting by `;` to prevent comment breaks.

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## 3. Migration Files Created / Modified

| File | Type | SHA-256 Checksum | Purpose |
|---|---|---|---|
| `migrations/003_enforce_hierarchy_composite_fk.sql` | Forward Migration | `df77adcc00aacfa2dac4da92bfc30272047614cb40f1809f445e4cac03a82897` | Adds composite hierarchy foreign key and class foreign key |
| `scripts/migrate.js` | Migration Runner | N/A | Safe exit codes, advisory lock release, and preflight hooks |
| `scripts/migration-status.js` | Status Reporter | N/A | Safe pool closure and exit handling |

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## 4. Tests Executed and Actual Results

All tests were executed against isolated disposable databases and the local development database.

### A. Isolated Runner & Preflight Scenarios (`scripts/test-step4-scenarios.js`)

| Scenario | Expected Behavior | Actual Result |
|---|---|---|
| **Fresh Database Migration** | Runs 001, 002, 003 cleanly | **PASS** (exited code 0) |
| **Idempotence / Re-execution** | Skips previously applied 003 | **PASS** (exited code 0) |
| **Checksum Mismatch Detection** | Detects tampered checksum | **PASS** (rejected with code 1) |
| **Preflight Data Anomaly Check** | Detects mismatched student/coordinator data and aborts before 003 | **PASS** (rejected with code 1, 003 not recorded) |

### B. Relational & Schema Integrity Tests (`tests/hierarchy-and-class-integrity.test.js`)

| Test Case | Constraint Tested | Actual Result |
|---|---|---|
| **1. Valid Student-Coordinator-ASM assignment** | `fk_student_coordinator_asm` | **PASS** (assigned successfully) |
| **2. Mismatched Coordinator and ASM assignment** | `fk_student_coordinator_asm` | **PASS** (rejected with FK constraint error) |
| **3. Invalid `class_id` assignment** | `fk_student_class` | **PASS** (rejected with FK constraint error) |
| **4. Nullable `class_id` and `ON DELETE SET NULL`** | `fk_student_class` | **PASS** (null allowed, class delete sets null) |

### C. Regression Suite (`tests/database-integrity.test.js`)

| Test Case | Description | Actual Result |
|---|---|---|
| **1. Duplicate mobile rejection** | `users.mobile_normalized` unique constraint | **PASS** |
| **2. Orphan area prevention** | `asm_profiles.area_id` foreign key | **PASS** |
| **3. Multi-Coordinator & Restrict policy** | Coordinator/Student restrict behavior | **PASS** |

### Test Summary
- **Total Test Suites**: 2 passed, 2 total
- **Total Tests**: 7 passed, 7 total (100% pass rate)

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## 5. Migration Status on Primary Development Database (`topiq`)

```text
=== Database Migration Status ===

┌─────────┬────┬─────────────────────────────────────────────┬────────────────────────────────────────────────────────────────────┬──────────────────────────┐
│ (index) │ id │ filename                                    │ checksum                                                           │ executed_at              │
├─────────┼────┼─────────────────────────────────────────────┼────────────────────────────────────────────────────────────────────┼──────────────────────────┤
│ 0       │ 1  │ '001_baseline.sql'                          │ '43a77bea004826847abffcdac3b249ed493fc8fbafa099197734d21837f0949e' │ 2026-10-09T08:47:44.000Z │
│ 1       │ 2  │ '002_add_referral_events_classes_audit.sql' │ '8311533d6dab533f134b59ccb75e198d8623a4b07bec47e21008ac31f015eb03' │ 2026-10-09T08:47:44.000Z │
│ 2       │ 3  │ '003_enforce_hierarchy_composite_fk.sql'    │ 'df77adcc00aacfa2dac4da92bfc30272047614cb40f1809f445e4cac03a82897' │ 2026-10-09T12:50:26.000Z │
└─────────┴────┴─────────────────────────────────────────────┴────────────────────────────────────────────────────────────────────┴──────────────────────────┘
```

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## 6. Remaining Issues

None. All three issues identified in the verification review have been resolved, verified, and locked in the version-controlled migration history.