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Salesforce Data Migration Tools Interview Questions and Answers Experienced

1. What happens when Data Loader fails during a bulk process?

Data Loader rolls back the entire batch of records in the failed transaction. You need to review the error file, fix issues, and reprocess only the failed records.

2. How does Data Import Wizard differ from Data Loader?

Data Import Wizard is web-based, user-friendly, supports fewer objects, and is suitable for small to medium data loads. Data Loader is a client app, supports all objects, large volumes, and offers advanced options.

3. Can Data Loader be used to update records that were inserted by Data Import Wizard?

Yes, Data Loader can update records inserted by Data Import Wizard, provided you have the record IDs or a unique external ID to match records.

4. How do you handle lookup relationship fields during data migration?

You first load parent object records, export their Salesforce IDs, then use these IDs to populate lookup fields in child records during migration.

5. What is the best practice for migrating data to objects with master-detail relationships?

Load the master records first, capture their Salesforce IDs, then load detail records referencing these IDs to maintain relationship integrity.

6. How can you automate large data migration in Salesforce?

Use Data Loader CLI mode with batch files or scripts to automate import/export tasks, handle retries, and schedule migrations.

7. What is an External ID and why is it important in data migration?

An External ID is a custom field marked as unique and indexed that helps match and upsert records during migration without relying on Salesforce record IDs.

8. Explain how upsert operation works in Data Loader.

Upsert inserts new records and updates existing ones based on an External ID or Salesforce record ID to avoid duplicates during migration.

9. What are the governor limits to be aware of during bulk data migration?

Bulk API limits include total API calls per 24 hours, batch size (max 10,000 records), heap size, and CPU time limits that can affect large migrations.

10. When should you prefer Bulk API over SOAP API in Data Loader?

Use Bulk API for large data volumes (>10,000 records) as it processes data asynchronously in batches and is more efficient for big loads.

11. How do you resolve CSV file encoding issues in Data Loader?

Ensure CSV files are saved in UTF-8 encoding, especially for special characters, to avoid data corruption during migration.

12. Can Data Loader handle attachments and files? How?

Yes, Data Loader can insert attachments by loading the Attachment object with proper ParentId and file path in the CSV.

13. How do you handle data migration rollback if something goes wrong?

Maintain backup exports before migration; use error logs to fix issues; re-import corrected data; consider transactional rollback with Bulk API batches.

14. What are the typical causes of Data Loader failures?

Common causes include validation rule failures, required field missing, incorrect data format, exceeding limits, and sharing rule restrictions.

15. How do you migrate data into Salesforce Communities?

Data migration to community users requires special consideration of profiles, roles, and sharing settings. Use Data Loader with appropriate user licenses.

16. How to manage dependencies in multi-object data migration?

Plan migration order: migrate parent objects first, resolve dependencies by exporting IDs, then migrate dependent child objects referencing those IDs.

17. What is the maximum batch size allowed by Data Loader for Bulk API?

Bulk API batch size max is 10,000 records per batch, but best practice is 200-2000 for optimal performance and error handling.

18. Can Data Loader run scheduled jobs? How?

Yes, Data Loader CLI can be scheduled using OS schedulers (Windows Task Scheduler, cron jobs) with command line scripts.

19. What are the limitations of Data Import Wizard?

Supports only select standard objects, no bulk API, limited file size (up to 100MB), no scheduling or automation, and limited advanced features.

20. How do you migrate picklist fields with different values between orgs?

Ensure picklist values exist in the target org before migration or map old values to new allowed values to avoid import errors.

21. What is the use of Salesforce Data Export and Import Wizard?

Data Export provides scheduled backups of data. Import Wizard is an easy-to-use web tool to load small to medium data volumes for select objects.

22. How do you handle large volume data migration without impacting org performance?

Use Bulk API with small batches, off-peak hours, disable triggers/validation rules temporarily, and monitor async job progress carefully.

23. How do you migrate formula fields or calculated fields?

Formula fields are calculated in real-time and do not need migration. Migrate the base fields/formula inputs only.

24. How do you handle encrypted fields during data migration?

Encrypted fields cannot be read or migrated via Data Loader unless running with "View Encrypted Data" permission, so migrate unencrypted copies if needed.

25. How do you migrate User records and maintain relationships?

Users are special objects. Usually migrated via data loading User object with required fields. Maintain references by updating related records with correct User IDs.

26. What are the error handling features of Data Loader?

Data Loader provides success and error CSV logs per batch to identify and fix failed records for reprocessing.

27. How do you handle record ownership during data migration?

Include the OwnerId field in the CSV to assign correct ownership; ensure the OwnerId exists in the target org.

28. Can Data Loader be used for exporting data as well?

Yes, Data Loader can export data via SOQL queries and save as CSV for backup or data transformation.

29. How do you migrate data for custom metadata types?

Custom metadata records are migrated using Metadata API tools like ANT or Salesforce CLI, not Data Loader.

30. How do you ensure data integrity during migration?

Pre-validate data, maintain referential integrity, test in sandbox, use External IDs, and post-migration verify record counts and relationships.