PowderCoatingLogix/sample-data/IMPORT_ERROR_FIXES.md

CSV Import Error Handling Improvements

Problem Solved

Original Issue: When importing CSV files, if a single record had a database constraint violation (like duplicate SKU or email), the entire import would crash with a database exception, providing a poor user experience.

Solution Applied

All three CSV import methods now use robust error handling that:

1. ✅ Validates all records in-memory first
2. ✅ Saves records one-by-one to isolate failures
3. ✅ Catches database exceptions gracefully
4. ✅ Skips problem records and continues importing
5. ✅ Provides detailed error/warning messages

Changes Made

1. Updated Sample Data Files

• inventory-items-sample.csv: Changed SKU prefix from PWD-*/CON-* to IMP-PWD-*/IMP-CON-*
  • Prevents conflicts with seed data
  • Also created inventory-items-sample-v2.csv as backup

2. Enhanced Import Service (CsvImportService.cs)

All Three Import Methods Now:

Customer Import (ImportCustomersAsync):

• Detects duplicate emails in database and within CSV file
• Saves each customer individually
• Catches database constraint violations
• Reports: "Row X: Customer with email 'Y' already exists in database. Skipping."

Catalog Items Import (ImportCatalogItemsAsync):

• Detects duplicate SKUs in database and within CSV file
• Saves each catalog item individually
• Catches database constraint violations
• Reports: "Row X: Catalog item with SKU 'Y' already exists in database. Skipping."

Inventory Import (ImportInventoryItemsAsync):

• Detects duplicate SKUs in database and within CSV file
• Saves each inventory item individually
• Catches database constraint violations
• Reports: "Row X: SKU 'Y' already exists in database. Skipping."

3. Updated Documentation

• README.md: Added troubleshooting section for duplicate SKU/email errors
• Explains how to handle conflicts (use new sample files, delete existing data, or edit CSV)

How It Works Now

Before (Old Behavior):

1. Read CSV file
2. Validate all rows
3. Add all rows to DbContext
4. Call SaveChanges() once
5. ❌ If ANY row fails → entire import crashes with exception

After (New Behavior):

1. Read CSV file
2. Validate all rows (in-memory duplicate detection)
3. Build list of valid items to import
4. Loop through each item:
   a. Add to DbContext
   b. Call SaveChanges()
   c. If success → increment success count
   d. If database error → log warning, rollback, continue to next
5. ✅ Return detailed results: X succeeded, Y failed

Error Messages You'll See

Duplicate Detection (In-Memory):

• ✅ Row 5: Customer with email 'john@example.com' already exists in database. Skipping.
• ✅ Row 12: Duplicate SKU 'IMP-PWD-BLK-001' found in import file. Skipping.

Database Constraint Violations:

• ✅ Row 8: SKU 'PWD-BLK-001' already exists in database (detected during save). Skipping.
• ✅ Row 15: Database error - Cannot insert duplicate key...

Missing Required Fields:

• ✅ Row 3: SKU is required.
• ✅ Row 7: CompanyName is required.

Warnings (Non-Critical):

• ⚠️ Row 10: Pricing tier 'DIAMOND' not found. Customer will have no pricing tier.
• ⚠️ Row 22: Category 'Automotive/Wheels' created automatically.

Example Import Results

Import Results:
✅ Success: 18 records imported
❌ Errors: 2 records skipped

Warnings:
- Row 5: Customer with email 'jane@acme.com' already exists in database. Skipping.
- Row 12: Pricing tier 'GOLD' not found. Customer will have no pricing tier.

Errors:
- Row 8: SKU is required.
- Row 15: Duplicate SKU 'IMP-PWD-BLK-001' found in import file. Skipping.

Testing the Fix

Test Case 1: Import with Existing Data

1. Run Platform Management > Seed Data to create demo inventory
2. Try to import inventory-items-sample-v2.csv (old SKU format)
3. ✅ Expected: Graceful warnings, no crash, other records still import

Test Case 2: Import Fresh Data

1. Use the updated inventory-items-sample.csv (IMP- prefix)
2. Upload to Tools > CSV Bulk Import > Inventory tab
3. ✅ Expected: All 25 records import successfully

Test Case 3: Duplicate Within CSV

1. Edit any CSV file and duplicate a row (same SKU or email)
2. Upload the file
3. ✅ Expected: First occurrence imports, second gets warning "found in import file"

Test Case 4: Invalid Data

1. Edit CSV and remove required field (SKU, CompanyName, etc.)
2. Upload the file
3. ✅ Expected: Row skipped with clear error, other rows still import

Benefits

1. No More Crashes: Database exceptions don't crash the import
2. Partial Imports Work: 18 out of 20 records? No problem!
3. Clear Feedback: Know exactly which rows failed and why
4. Data Integrity: Transaction rollback prevents partial saves
5. User-Friendly: Non-technical users can understand error messages

Technical Details

Transaction Handling

Each record is saved in its own mini-transaction:

try
{
    await _unitOfWork.InventoryItems.AddAsync(item);
    await _unitOfWork.CompleteAsync();  // Commit this one record
    result.SuccessCount++;
}
catch (DbUpdateException dbEx)
{
    result.Warnings.Add($"Row {rowNumber}: SKU already exists. Skipping.");
    await uow.RollbackTransactionAsync();  // Rollback just this record
    // Continue to next record
}

Duplicate Detection Strategy

1. First Pass (In-Memory): Check against existing database data (fast)
2. Second Pass (In-Memory): Check for duplicates within the CSV file itself
3. Third Pass (Database): Catch any race conditions or concurrent inserts

Files Modified

1. ✅ PowderCoating.Infrastructure/Services/CsvImportService.cs (3 methods updated)
2. ✅ sample-data/inventory-items-sample.csv (SKUs updated)
3. ✅ sample-data/inventory-items-sample-v2.csv (created)
4. ✅ sample-data/README.md (troubleshooting added)
5. ✅ sample-data/IMPORT_ERROR_FIXES.md (this file)

Build Status

✅ Build Succeeded - 0 Errors, 0 New Warnings

Next Steps

1. Test the imports with the updated sample CSV files
2. Re-import inventory using the new inventory-items-sample.csv (IMP- prefix)
3. Delete old inventory items if you have duplicates from seed data (optional)
4. Create your own CSV files using the updated template format

Questions?

• Sample files not importing? Check the README.md troubleshooting section
• Still seeing errors? The error messages now tell you exactly what's wrong
• Want to reset data? Delete existing records or use new SKU prefixes in your CSV