# Duplicate, matching and validation rules

*Platform Administrator Study Guide · Data and Analytics Management · Last updated September 26, 2026 · https://certifyforce.com/study-guide/platform-administrator/data-and-analytics-management/duplicate-matching-and-validation-rules*

How matching rules and duplicate rules work together to alert, block or report on duplicates at save time, and how validation rules enforce data standards, where their errors appear, how to exempt a user, and where they run in the save order.

- Certification: Salesforce Platform Administrator
- Exam section: Data and Analytics Management
- Study guide: https://certifyforce.com/study-guide/platform-administrator

**Official exam objective:**

> Describe the capabilities and implications of data validation tools (duplicate and matching rules, validation rules).

## What the exam expects

- Explain how a duplicate rule depends on an active matching rule, and diagnose why duplicates still get saved.
- Choose the duplicate rule action (allow with an alert, block, report) and scope (same object or cross-object, custom fields, conditions) for a requirement.
- Pick an exact or fuzzy matching method for a field, and know what duplicate management does not do (it never merges or deletes records on its own, and it does not clean up existing data at activation).
- Write a validation rule that fires conditionally, place its error message on the right field, and exempt a specific user with a custom permission.
- Predict how validation rules interact with other save-time logic such as before-save flows and API loads.

## Key facts

| Fact | Detail | Source |
|---|---|---|
| Duplicate rule prerequisite | Every matching rule it uses must be active | [Customize Duplicate Rules](https://help.salesforce.com/s/articleView?id=sales.duplicate_rules_create.htm&type=5) |
| Matching rule activation | Takes time; email sent when ready | [Customize Matching Rules](https://help.salesforce.com/s/articleView?id=sales.matching_rules_create.htm&type=5) |
| Fields per matching rule | Up to 10 | [Customize Matching Rules](https://help.salesforce.com/s/articleView?id=sales.matching_rules_create.htm&type=5) |
| Active duplicate rules per object | Up to five | [Things to Know](https://help.salesforce.com/s/articleView?language=en_US&id=sales.duplicate_rules_overview.htm&type=5) |
| Matching rules per duplicate rule | Up to three | [Things to Know](https://help.salesforce.com/s/articleView?language=en_US&id=sales.duplicate_rules_overview.htm&type=5) |
| Duplicate rule actions | Allow (alert, report) or Block | [Stop Duplicate Records](https://help.salesforce.com/s/articleView?id=sales.duplicate_prevention.htm&language=en_US&type=5), [Customize Duplicate Rules](https://help.salesforce.com/s/articleView?id=sales.duplicate_rules_create.htm&type=5) |
| Duplicates shown in Lightning alert | Up to 15 | [Stop Duplicate Records](https://help.salesforce.com/s/articleView?id=sales.duplicate_prevention.htm&language=en_US&type=5) |
| When duplicate rules run | On create or edit, not retroactively | [Things to Know](https://help.salesforce.com/s/articleView?language=en_US&id=sales.duplicate_rules_overview.htm&type=5) |
| Fuzzy: Company Name | Strips words like Inc and Corp before comparing | [Matching Methods](https://help.salesforce.com/s/articleView?id=sales.matching_rules_matching_methods.htm&type=5) |
| Validation formula result | True means invalid, save stopped | [Validation Rules](https://help.salesforce.com/s/articleView?id=platform.fields_about_field_validation.htm&type=5) |
| Error location | Top of Page or a specific field | [Validation Rules Fields](https://help.salesforce.com/s/articleView?id=platform.fields_validation_rules_fields.htm&type=5) |
| Validation rules and the API | Apply to API and integration saves too | [Validation Rules](https://help.salesforce.com/s/articleView?id=platform.fields_about_field_validation.htm&type=5) |
| Before-save flow timing | Runs before custom validation rules | [Order of Execution](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_triggers_order_of_execution.htm) |

## Check yourself

- What must be true of a matching rule before a duplicate rule that uses it can be activated? → It must be active, and matching rule activation runs in the background ([Customize Duplicate Rules](https://help.salesforce.com/s/articleView?id=sales.duplicate_rules_create.htm&type=5))
- Why can an exact matching rule miss "Acme Inc." versus "Acme Incorporated"? → Exact needs identical strings; Fuzzy: Company Name strips words like Inc before comparing ([Matching Methods](https://help.salesforce.com/s/articleView?id=sales.matching_rules_matching_methods.htm&type=5))
- When do duplicate rules evaluate a record, and what happens to duplicates that already exist? → Only when a record is created or edited; existing duplicates stay until someone merges them ([Things to Know](https://help.salesforce.com/s/articleView?language=en_US&id=sales.duplicate_rules_overview.htm&type=5))
- How do you let one integration user skip a validation rule while it stays active for everyone else? → Reference a custom permission with $Permission in the formula and assign it through a permission set ([Global Variables](https://help.salesforce.com/s/articleView?id=platform.dev_understanding_global_variables.htm&type=5))
- Why does a validation rule see a value the user never entered? → A before-save flow set it, and before-save flows run before custom validation rules ([Order of Execution](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_triggers_order_of_execution.htm))

## Sources

- [Things to Know About Duplicate Rules](https://help.salesforce.com/s/articleView?language=en_US&id=sales.duplicate_rules_overview.htm&type=5)
- [Customize Duplicate Rules](https://help.salesforce.com/s/articleView?id=sales.duplicate_rules_create.htm&type=5)
- [Stop Users from Creating Duplicate Records](https://help.salesforce.com/s/articleView?id=sales.duplicate_prevention.htm&language=en_US&type=5)
- [Customize Matching Rules](https://help.salesforce.com/s/articleView?id=sales.matching_rules_create.htm&type=5)
- [Matching Methods Used in Matching Rules](https://help.salesforce.com/s/articleView?id=sales.matching_rules_matching_methods.htm&type=5)
- [Validation Rules](https://help.salesforce.com/s/articleView?id=platform.fields_about_field_validation.htm&type=5)
- [Validation Rules Fields](https://help.salesforce.com/s/articleView?id=platform.fields_validation_rules_fields.htm&type=5)
- [Global Variables](https://help.salesforce.com/s/articleView?id=platform.dev_understanding_global_variables.htm&type=5)
- [Triggers and Order of Execution](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_triggers_order_of_execution.htm)

## About the full unit

The "Core concepts", "Exam traps" and "Worked scenario" sections of this unit, its 9 linked practice questions, and unlimited timed mock exams are included with the Platform Administrator pack (USD $19): https://certifyforce.com/practice-exams