# 🔄 Database Triggers Implementation for v2

**Date:** January 30, 2026  
**Status:** ✅ Ready for Implementation  
**Priority:** HIGH

---

## 📋 SQL Triggers for v2 scanfg_orders

### Current Situation
The v2 application has the scanfg_orders table but:
- ❌ No database triggers for automatic calculation
- ❌ CP_base_code not extracted automatically
- ❌ Quantities may be entered manually or not calculated

### Required Implementation

#### 1. Add Generated Column (if not present)

```sql
-- Check if cp_base_code column exists
SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS 
WHERE TABLE_NAME = 'scanfg_orders' AND COLUMN_NAME = 'cp_base_code';

-- If not exists, add it:
ALTER TABLE scanfg_orders 
ADD COLUMN cp_base_code VARCHAR(10) 
GENERATED ALWAYS AS (SUBSTRING(CP_full_code, 1, 10)) STORED;

-- Add index for performance
CREATE INDEX idx_cp_base_code ON scanfg_orders(cp_base_code);
```

#### 2. Create Trigger for Automatic Quantity Calculation

```sql
-- Drop existing trigger if present
DROP TRIGGER IF EXISTS set_quantities_fg;

-- Create new trigger
CREATE TRIGGER set_quantities_fg
BEFORE INSERT ON scanfg_orders
FOR EACH ROW
BEGIN
    -- Count how many APPROVED entries exist for this CP_base_code
    SET @approved = (
        SELECT COUNT(*) FROM scanfg_orders 
        WHERE SUBSTRING(CP_full_code, 1, 10) = SUBSTRING(NEW.CP_full_code, 1, 10)
        AND quality_code = 0
    );
    
    -- Count how many REJECTED entries exist for this CP_base_code  
    SET @rejected = (
        SELECT COUNT(*) FROM scanfg_orders 
        WHERE SUBSTRING(CP_full_code, 1, 10) = SUBSTRING(NEW.CP_full_code, 1, 10)
        AND quality_code != 0
    );
    
    -- Set quantities based on this new row's quality_code
    IF NEW.quality_code = 0 THEN
        -- Approved scan: increment approved count
        SET NEW.approved_quantity = @approved + 1;
        SET NEW.rejected_quantity = @rejected;
    ELSE
        -- Rejected scan: increment rejected count
        SET NEW.approved_quantity = @approved;
        SET NEW.rejected_quantity = @rejected + 1;
    END IF;
END;
```

#### 3. Same for scan1_orders (T1 Phase)

```sql
DROP TRIGGER IF EXISTS set_quantities_scan1;

CREATE TRIGGER set_quantities_scan1
BEFORE INSERT ON scan1_orders
FOR EACH ROW
BEGIN
    SET @approved = (
        SELECT COUNT(*) FROM scan1_orders 
        WHERE SUBSTRING(CP_full_code, 1, 10) = SUBSTRING(NEW.CP_full_code, 1, 10)
        AND quality_code = 0
    );
    
    SET @rejected = (
        SELECT COUNT(*) FROM scan1_orders 
        WHERE SUBSTRING(CP_full_code, 1, 10) = SUBSTRING(NEW.CP_full_code, 1, 10)
        AND quality_code != 0
    );
    
    IF NEW.quality_code = 0 THEN
        SET NEW.approved_quantity = @approved + 1;
        SET NEW.rejected_quantity = @rejected;
    ELSE
        SET NEW.approved_quantity = @approved;
        SET NEW.rejected_quantity = @rejected + 1;
    END IF;
END;
```

---

## 🔍 Verification Queries

### Check if Triggers Exist
```sql
SELECT TRIGGER_NAME, TRIGGER_SCHEMA, TRIGGER_TABLE, ACTION_STATEMENT
FROM INFORMATION_SCHEMA.TRIGGERS
WHERE TRIGGER_SCHEMA = 'quality_app_v2'
AND TRIGGER_TABLE IN ('scanfg_orders', 'scan1_orders');
```

### Verify Trigger is Working
```sql
-- Insert test record
INSERT INTO scanfg_orders (operator_code, CP_full_code, OC1_code, OC2_code, quality_code, date, time)
VALUES ('OP01', 'CP00000001-0001', 'OC01', 'OC02', 0, CURDATE(), CURTIME());

-- Check if quantities were set automatically
SELECT Id, CP_full_code, quality_code, approved_quantity, rejected_quantity 
FROM scanfg_orders 
WHERE CP_full_code = 'CP00000001-0001';

-- Should show: approved_quantity = 1, rejected_quantity = 0
```

### Full Test Scenario
```sql
-- Step 1: Insert approved record
INSERT INTO scanfg_orders (operator_code, CP_full_code, OC1_code, OC2_code, quality_code, date, time)
VALUES ('OP01', 'CP00000001-0001', 'OC01', 'OC02', 0, CURDATE(), CURTIME());
-- Expected: approved_qty=1, rejected_qty=0

-- Step 2: Insert another approved record
INSERT INTO scanfg_orders (operator_code, CP_full_code, OC1_code, OC2_code, quality_code, date, time)
VALUES ('OP02', 'CP00000001-0002', 'OC01', 'OC02', 0, CURDATE(), CURTIME());
-- Expected: approved_qty=2, rejected_qty=0

-- Step 3: Insert rejected record
INSERT INTO scanfg_orders (operator_code, CP_full_code, OC1_code, OC2_code, quality_code, date, time)
VALUES ('OP01', 'CP00000001-0003', 'OC01', 'OC02', 2, CURDATE(), CURTIME());
-- Expected: approved_qty=2, rejected_qty=1

-- Verify all records
SELECT CP_full_code, quality_code, approved_quantity, rejected_quantity 
FROM scanfg_orders 
WHERE SUBSTRING(CP_full_code, 1, 10) = 'CP00000001'
ORDER BY Id;
```

---

## 🔧 Integration Points in Python Code

### 1. Database Initialization (initialize_db.py)

Add trigger creation to the database setup:

```python
def create_scan_triggers():
    """Create triggers for automatic quantity calculation"""
    try:
        conn = get_db()
        cursor = conn.cursor()
        
        # Drop existing triggers
        cursor.execute("DROP TRIGGER IF EXISTS set_quantities_fg")
        cursor.execute("DROP TRIGGER IF EXISTS set_quantities_scan1")
        
        # Create scanfg_orders trigger
        cursor.execute("""
            CREATE TRIGGER set_quantities_fg
            BEFORE INSERT ON scanfg_orders
            FOR EACH ROW
            BEGIN
                SET @approved = (SELECT COUNT(*) FROM scanfg_orders 
                                 WHERE SUBSTRING(CP_full_code, 1, 10) = SUBSTRING(NEW.CP_full_code, 1, 10)
                                 AND quality_code = 0);
                SET @rejected = (SELECT COUNT(*) FROM scanfg_orders 
                                 WHERE SUBSTRING(CP_full_code, 1, 10) = SUBSTRING(NEW.CP_full_code, 1, 10)
                                 AND quality_code != 0);
                
                IF NEW.quality_code = 0 THEN
                    SET NEW.approved_quantity = @approved + 1;
                    SET NEW.rejected_quantity = @rejected;
                ELSE
                    SET NEW.approved_quantity = @approved;
                    SET NEW.rejected_quantity = @rejected + 1;
                END IF;
            END
        """)
        
        logger.info("✓ Trigger 'set_quantities_fg' created")
        
        # Create scan1_orders trigger (similar)
        cursor.execute("""
            CREATE TRIGGER set_quantities_scan1
            BEFORE INSERT ON scan1_orders
            FOR EACH ROW
            BEGIN
                SET @approved = (SELECT COUNT(*) FROM scan1_orders 
                                 WHERE SUBSTRING(CP_full_code, 1, 10) = SUBSTRING(NEW.CP_full_code, 1, 10)
                                 AND quality_code = 0);
                SET @rejected = (SELECT COUNT(*) FROM scan1_orders 
                                 WHERE SUBSTRING(CP_full_code, 1, 10) = SUBSTRING(NEW.CP_full_code, 1, 10)
                                 AND quality_code != 0);
                
                IF NEW.quality_code = 0 THEN
                    SET NEW.approved_quantity = @approved + 1;
                    SET NEW.rejected_quantity = @rejected;
                ELSE
                    SET NEW.approved_quantity = @approved;
                    SET NEW.rejected_quantity = @rejected + 1;
                END IF;
            END
        """)
        
        logger.info("✓ Trigger 'set_quantities_scan1' created")
        
        conn.commit()
        cursor.close()
        return True
        
    except Exception as e:
        logger.error(f"✗ Error creating triggers: {e}")
        return False
```

### 2. FG Scan Form (fg_scan.html)

Ensure quality_code is set correctly:

```python
# In routes.py fg_scan endpoint
quality_status = request.form.get('quality_code', '0')  # From form

# Map user input to quality_code
if quality_status.lower() in ['approved', '0']:
    quality_code = 0  # Approved
else:
    quality_code = 1  # Rejected (or 2, 3, etc.)

# Insert record (trigger will auto-calculate quantities)
cursor.execute("""
    INSERT INTO scanfg_orders 
    (operator_code, CP_full_code, OC1_code, OC2_code, quality_code, date, time, box_id, location_id)
    VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s)
""", (
    operator_code, cp_full_code, oc1_code, oc2_code, quality_code,
    date, time, box_id, location_id
))

# quantities are automatically set by trigger!
```

### 3. Warehouse Inventory Display

The quantities are now automatically available:

```sql
-- In warehouse.py get_cp_inventory_list()
SELECT 
    s.CP_full_code,
    SUBSTRING(s.CP_full_code, 1, 10) as cp_base,
    SUM(s.approved_quantity) as total_approved,  -- Auto-calculated
    SUM(s.rejected_quantity) as total_rejected,  -- Auto-calculated
    ...
FROM scanfg_orders s
...
```

---

## 📊 Data Migration

For existing records in the database:

```sql
-- Recalculate quantities for all existing records
UPDATE scanfg_orders s1
SET 
    approved_quantity = (
        SELECT COUNT(*) FROM scanfg_orders s2
        WHERE SUBSTRING(s2.CP_full_code, 1, 10) = SUBSTRING(s1.CP_full_code, 1, 10)
        AND s2.quality_code = 0
        AND s2.Id <= s1.Id  -- Only count up to current record
    ),
    rejected_quantity = (
        SELECT COUNT(*) FROM scanfg_orders s2
        WHERE SUBSTRING(s2.CP_full_code, 1, 10) = SUBSTRING(s1.CP_full_code, 1, 10)
        AND s2.quality_code != 0
        AND s2.Id <= s1.Id  -- Only count up to current record
    );
```

---

## ✅ Checklist

- [ ] Add cp_base_code generated column to scanfg_orders
- [ ] Add cp_base_code generated column to scan1_orders
- [ ] Create set_quantities_fg trigger
- [ ] Create set_quantities_scan1 trigger
- [ ] Test with sample inserts
- [ ] Verify trigger working correctly
- [ ] Update initialize_db.py to create triggers
- [ ] Update db_schema_verifier.py to verify triggers exist
- [ ] Test with production-like data volume
- [ ] Document for team
- [ ] Deploy to production

---

## 🚀 Execution Steps

### Step 1: Test Locally
```bash
# Connect to test database
mysql -h localhost -u root -p quality_app_v2

# Run verification query
SELECT TRIGGER_NAME FROM INFORMATION_SCHEMA.TRIGGERS 
WHERE TRIGGER_TABLE IN ('scanfg_orders', 'scan1_orders');
```

### Step 2: Add to Schema Verifier
Update `db_schema_verifier.py` to check and recreate triggers if missing

### Step 3: Update initialize_db.py
Add trigger creation to database initialization sequence

### Step 4: Deploy
- Restart application
- Verify triggers created in database
- Test with new FG scan entries

---

## 📝 Notes

- Triggers execute **BEFORE INSERT** (before record is written to DB)
- Quantities are **immutable** after insertion (set once)
- Grouping is by **CP_base_code** (8 digits), not full code
- Compatible with existing data and warehouse features
- Maintains consistency with legacy application behavior

---

**Priority:** HIGH  
**Effort:** MEDIUM  
**Impact:** Data Accuracy, Report Correctness