When working with Informatica MDM, validation rules are essential for maintaining data quality. While predefined rule types cover most use cases, custom validation rules give us the flexibility to address complex, domain-specific scenarios.
๐งฉ What Are Custom Validation Rules?
Custom validation rules allow you to write SQL-based logic for validating data that goes beyond standard rule capabilities. They are extremely powerful, but there’s a catch:
Informatica MDM does not validate your SQL at design time.
That means if your query has errors, you might only discover them at runtime—during a Load or Revalidate job.
⚠️ The Surprising Behavior I Encountered
Recently, I ran into three key issues while working with custom validation rules:
1. Rule Not Triggering in Load, But Working in Revalidate
Turns out, the custom rule depended on a child table, but during the Load job, the child data hadn’t been loaded yet. So, the rule did not work. Revalidate worked fine because all the data was already present.
2. Rule Worked in Load, Failed in Revalidate
Here, I used aliases in the rule. Specifically, I referenced s.*, which points to staging columns. This worked during Load but failed during Revalidate because staging columns aren’t available. You have to change your query such a way that it will work both at load and at revalidate job.
3. Performance Bottleneck During Revalidate
The Revalidate job was taking over 24 hours. After optimizing the SQL logic (replaced IN with EXISTS), the job completed in under an hour.
Pro tip: Custom rules can be expensive—always evaluate performance on large datasets.
✅ Best Practices for Custom Validation Rules
Here are some lessons I now live by:
1. ๐ Test SQL Outside MDM First
Use a SQL client with real or sample data before pushing changes to Hub Console.
2. ๐ก️ Write Defensive SQL
Handle edge cases. Use IS NULL, safe joins, and anticipate missing data during the Load phase.
3. ๐งพ Be Descriptive
Name rules meaningfully and include detailed descriptions. You (and your teammates) will thank you later.
4. ๐ Test Both Load & Revalidate
Always validate both paths. Don’t assume what works in one will work in the other.
5. ๐ Know the Dependencies
Understand if your rule depends on data loaded by other mappings or child tables.
6. ๐ Check Job Logs Thoroughly
Often, rules don’t error—they just silently skip. Review cleanse/validation logs for subtle hints.
7. ๐ Version Control Your SQL
Keep SQL scripts versioned in Git or another system. This helps with collaboration, rollbacks, and audits.
๐ Final Thoughts
Custom validation rules are indispensable in complex MDM implementations. By following these best practices, you can avoid common pitfalls and ensure data validation remains accurate and consistent across all jobs.
Have you experienced any challenging behavior with validation rules in MDM? Drop a comment—I’d love to hear your stories!