To fix MIXED_DML_OPERATION error(setup and non-setup objects) in Salesforce

The following error will be occured if you’re trying to perform DML operation on both setup and non-setup objects in the same transation.

` MIXED_DML_OPERATION, DML operation on setup object is not permitted after you have updated a non-setup object (or vice versa): CustomObject__c, original object: User: [] `

Here is the sample code that can explain this case.

Setup objects

So, which objects are setup objects in Salesforce?
Setup objects are the sObjects that affect the user’s access to records in the organization. For operations with correct access-level permissions, you must insert or update these types of sObject in a different transaction.

Here are examples of the Setup Objects:
    fields: UserRoleId, IsActive, ForecastEnabled, IsPortalEnabled, Username, ProfileId


To fix this kind of error, you can perform DML operations on more than one transation, e.g. using a Future method.

Happy Coding!

Reference :

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