> For the complete documentation index, see [llms.txt](https://help.delpha.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.delpha.io/delpha-for-salesforce/use-cases-setup/duplicate/duplicate-merge/related-object-rules.md).

# Related Object Rules

### Overview

When merging two records (e.g., Contact A and Contact B), Salesforce automatically re-parents all child records to the surviving Master Record. This can create a new problem: Child Duplicates.

* *Scenario:* Contact A has an Opportunity named "Q3 Deal." Contact B *also* has a duplicate Opportunity named "Q3 Deal."
* *Result without rules:* The final merged Contact will have *two* identical "Q3 Deal" Opportunities in its related list.
* *Solution:* Related Object Rules allow you to detect and merge these child duplicates automatically during the parent merge process.

### How to Configure Related Object Rules

1. Access the Section: In Merge Settings, expand Related Object Rules.
2. Add New Rule: Click the New button.
3. Select the Related Object: Choose the child object you want to manage (e.g., `Opportunity`, `Case`, or a Custom Object).
4. Define the Relationship:
   * Related Object Field: Select the lookup field that connects the child to the parent (e.g., `AccountId` or `ContactId`).
5. Define Deduplication Logic:
   * Duplicate Group Expression: This works like a unique key. Select the field(s) that identify a duplicate *within the context of this parent*.
     * *Example:* For Opportunities, you might select `Name`. If two Opportunities have the exact same `Name` on the same Account, Delpha treats them as duplicates.
     * *Note:* This uses strict exact matching (full match, no fuzzy logic).
6. Select the "Winner" Strategy:
   * Selection Criteria: Decide which of the duplicate child records should be kept.
     * `Keep Based on Newest Record`: Retains the most recently created item.
     * `Keep based On Oldest Record`: Retains the original item.
     * `Keep Based on Latest Modified Record`: Retains the one with the most recent updates.
     * `Keep Master Record Items`: Always prioritizes the child record that was already owned by the Master parent record.

### Example Configuration: Deduplicating Opportunities

To ensure you don't end up with duplicate opportunities after merging Accounts:

* Related Object: `Opportunity`.
* Duplicate Group Expression: `Name` (and optionally `CloseDate`).
* Selection Criteria: `Keep Based on Latest Modified Record`.
* Result: If both Accounts have an opportunity named "Big Deal," only the one updated most recently is kept. The other is deleted/merged.

***


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