Merge
By the end of this lesson, you'll be able to:
- Explain what merge does and the problem it solves (duplicate records)
- Identify which record becomes the "master" in a merge
- Recognize merge's specific limitations (record count, supported objects)
Prerequisites: "Delete and Undelete"
The problem: duplicate records
Imagine two Account records both represent "Acme Logistics" — created separately by two different people, each with their own related Contact and Opportunity records. Simply deleting one loses its related data; simply keeping both means data about the same company is split across two records. merge solves this directly.
Merging two records into one
Account masterAccount = [SELECT Id FROM Account WHERE Name = 'Acme Logistics' ORDER BY CreatedDate ASC LIMIT 1];
Account duplicateAccount = [SELECT Id FROM Account WHERE Name = 'Acme Logistics' ORDER BY CreatedDate DESC LIMIT 1];
merge masterAccount duplicateAccount;masterAccount survives; duplicateAccount is deleted, and — critically — any Contact, Opportunity, or other related record that pointed at duplicateAccount is automatically re-pointed to masterAccount instead. Nothing related to the duplicate is silently lost.
Real limitations to know about
mergeonly works on a handful of standard objects (Account,Contact,Lead, and a few others) — it isn't a general-purpose tool for arbitrary custom objects.- You can merge at most 3 records into 1 master in a single statement.
- Once merged, the operation cannot be undone the way
delete/undeletecan — choosing the correct master record matters, since the decision is effectively permanent.
Exercise
As a comment, explain what happens to a Contact that was related to the duplicate Account after a merge.
Show hint
Think about what merge does beyond just deleting the duplicate.
Merge Quiz
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Summary
merge combines duplicate records into one, keeping a chosen "master" record and re-pointing related records — the standard fix for accidental duplicates.