# System Fields - Quick Reference

## What Are System Fields?

Fields that are automatically managed by the system and should never require user input:
- `id` - Unique record identifier (UUID)
- `tenantId` - Tenant ownership
- `ownerId` - User who owns the record
- `created_at` - Record creation timestamp
- `updated_at` - Last modification timestamp

## Frontend Treatment

### Hidden from Edit Forms
System fields are automatically hidden from create/edit forms:
```
❌ Not visible to users
❌ Not validated
❌ Not submitted to API
```

### Visible on Detail/List Views (Read-Only)
System fields appear on detail and list views as read-only information:
```
✅ Visible to users (informational)
✅ Not editable
✅ Shows metadata about records
```

## Backend Treatment

### Auto-Set on Insert
When creating a record, Objection model hooks auto-set:
```javascript
{
  $beforeInsert() {
    if (!this.id) this.id = randomUUID();
    if (!this.created_at) this.created_at = now();
    if (!this.updated_at) this.updated_at = now();
  }
}
```

### Auto-Set on Update
When updating a record:
```javascript
{
  $beforeUpdate() {
    this.updated_at = now();  // Always update timestamp
  }
}
```

### Protected from Updates
Backend filters out system fields in update requests:
```typescript
delete allowedData.ownerId;      // Can't change owner
delete allowedData.id;            // Can't change ID
delete allowedData.created_at;   // Can't change creation time
delete allowedData.tenantId;     // Can't change tenant
```

## Field Status Matrix

| Field | Value | Source | Immutable | User Editable |
|-------|-------|--------|-----------|---------------|
| id | UUID | System | ✓ Yes | ✗ No |
| tenantId | UUID | System | ✓ Yes | ✗ No |
| ownerId | UUID | Auth context | ✓ Yes* | ✗ No |
| created_at | Timestamp | Database | ✓ Yes | ✗ No |
| updated_at | Timestamp | Database | ✗ No** | ✗ No |

*ownerId: Set once on creation, immutable after
**updated_at: Changes on every update (automatic)

## How It Works

### Create Record
```
User form input:
┌─────────────────────┐
│ Name: "Acme Corp"   │
│ Revenue: 1000000    │
└─────────────────────┘
          ↓
Backend Objection Model:
┌──────────────────────────────────────┐
│ INSERT INTO accounts (               │
│   id,            ← Generated UUID    │
│   name,          ← User input        │
│   revenue,       ← User input        │
│   ownerId,       ← From auth         │
│   created_at,    ← Current timestamp │
│   updated_at,    ← Current timestamp │
│   tenantId       ← From context      │
│ ) VALUES (...)                       │
└──────────────────────────────────────┘
```

### Update Record
```
User form input:
┌─────────────────────┐
│ Revenue: 1500000    │
└─────────────────────┘
          ↓
Backend filters:
┌──────────────────────────────────┐
│ UPDATE accounts SET              │
│   revenue = 1500000,  ← Allowed  │
│   updated_at = now()  ← Auto     │
│ WHERE id = abc123                │
│                                  │
│ ownerId, created_at stay same    │
└──────────────────────────────────┘
```

## Validation Errors - Solved

### Before Fix
```
"Owner is required"
"Created At is required"
"Updated At is required"
```

### After Fix
```
✓ No system field validation errors
✓ System fields hidden from forms
✓ System fields auto-managed by backend
```

## Field Detection Logic

Frontend identifies system fields by:
1. **Field name** - Known system field names
2. **isSystem flag** - Backend marker (`isSystem: true`)

Either condition causes field to be hidden from edit:
```typescript
const systemFieldNames = ['id', 'tenantId', 'ownerId', 'created_at', 'updated_at', ...]
const isSystemField = Boolean(fieldDef.isSystem)
const isAutoGeneratedField = systemFieldNames.includes(fieldDef.apiName)

if (isSystemField || isAutoGeneratedField) {
  showOnEdit = false  // Hide from edit form
}
```

## Backward Compatibility

✅ Works with:
- **New objects** - Created with proper flags
- **Old objects** - Flags added on-the-fly during retrieval
- **Mixed environments** - Both types work simultaneously

## Common Tasks

### Create a New Record
```
1. Click "Create [Object]"
2. See form with user-editable fields only
3. Fill in required fields
4. Click "Save"
5. System auto-sets: id, ownerId, created_at, updated_at ✓
```

### View Record Details
```
1. Click record name
2. See all fields including system fields
3. System fields shown read-only:
   - Created: [date] (when created)
   - Modified: [date] (when last updated)
   - Owner: [user name] (who owns it) ✓
```

### Update Record
```
1. Click "Edit [Record]"
2. See form with user-editable fields only
3. Change values
4. Click "Save"
5. System auto-updates: updated_at ✓
6. ownerId and created_at unchanged ✓
```

## Related Files

- [SYSTEM_FIELDS_FIX.md](SYSTEM_FIELDS_FIX.md) - Detailed fix documentation
- [OWNER_FIELD_VALIDATION_FIX.md](OWNER_FIELD_VALIDATION_FIX.md) - Owner field specific fix
- [OBJECTION_MODEL_SYSTEM.md](OBJECTION_MODEL_SYSTEM.md) - Model system architecture
- [backend/src/object/object.service.ts](backend/src/object/object.service.ts#L278-L291) - Normalization code
- [frontend/composables/useFieldViews.ts](frontend/composables/useFieldViews.ts#L12-L20) - Frontend field detection