Last Updated on April 18, 2022 by Rakesh Gupta

Big Idea or Enduring Question:

• How do you resolve MIXED_DML_OPERATION: DML operation on setup object is not permitted after you have updated a non-setup object (or vice versa) error? 

The Record-Triggered Flow is a way of automating business processes. Record-Triggered Flow is a powerful tool for system administrators and developers to implement business processes without writing code. However, with great power comes great responsibility –  If a user starts creating a new flow for each requirement – or creating flows without understanding Salesforce limitations – then, a user may encounter many issues, either in the future or, while the testing/deployment phase. Let us start with one of the most common errors –  Mixed Data Manipulation Language (DML) Operation Error.

Objectives:

After reading this blog, you’ll be able to: 

• Understand what is mixed DML operation error
• Resolve mixed DML operation error
• and much more

What is a Mixed DML Operation Error?

In the end, Donna’s Flow will look like the following screenshot:

Almost there! Once everything looks good, click the Activate button.  

Proof of Concept

1. Create a new User in Salesforce, as shown in the following screenshot:
2. Once you’re done, click on the Save button. Boooommmm, you encounter a MIXED_DML_OPERATION error, as shown in the following screenshot:

👉 As mentioned earlier, the reason behind the error is, that we are assigning Permission Set Group record and creating Leave Balances in the same transaction. It means we are performing DML operations on setup and non-setup objects in the same transaction.

Fix MIXED_DML_OPERATION Error

To fix the MIXED_DML_OPERATION error in a Flow, we have to separate setup and non-setup objects transactions by using

• Scheduled Path 
• Async Path
• Pause element 
• Platform Event
• Scheduled-Triggered Flow
• Future callout via Apex

Perform the following instructions to solve the MIXED_DML_OPERATION error in a Flow using Scheduled Path. The best way to solve this problem is using Platform Event, given that we want to enforce one after save flow per object. 

Step 1: Clone Existing Flow 

1. Click Setup.
2. In the Quick Find box, type Flows.
3. Select Flows then click on the Flow Name that will be modified. In this case Auto Assign Permission Set Group.
4. Click on the Save As button at the top right of the Flow builder.
5. Click Save.

Step 2: Salesforce Flow – Add Scheduled Paths

The purpose of using a scheduled path is to execute the flow after 0 hours of user creation. The purpose of putting time-dependent action is to avoid MIXED DML errors.

1. Under Start, select Add Scheduled Paths (Optional).
2. Under SCHEDULED PATHS, click on the  New Scheduled Path.
3. Under Scheduled Path Details, enter the Label the API Name will auto-populate.
4. Time Source: User: Created Date
5. Offset Number: 0
6. Offset Options: Hours After
7. Advanced Options
   1. Batch Size: 200
8. Click Done.

Step 3: Adding a Get Record Element to Find the Leave Balance Record for User 

The next step is to use the Get Records element to find the leave balance record for the current record. 

1. On Flow Designer, below the 0 hr After node, click on the +icon and select the Get Records element.
2. Enter a name in the Label field; the API Name will auto-populate.
3. Select the Leave Balance object from the dropdown list.
4. Select All Conditions Are Met (AND). 
5. Set Filter Conditions
   1. Row 1:
      1. Field: Employee_Name__c
      2. Operator: Equals
      3. Value: {!$Record.Id}
6. How Many Records to Store:
   1. select Only the first record
7. How to Store Record Data:
   1. Choose the option to Automatically store all fields. 
8. Click Done.

Step 4: Using Decision Element to Check If Leave Balance Record was Found or Not 

Now, will use the Decision element to check if the previous Get Records element returns a leave balance record or not. 

1. On Flow Designer, click on the +icon and select the Decision element.
2. Enter a name in the Label field; the API Name will auto-populate.
3. Under Outcome Details, enter the Label the API Name will auto-populate.
4. Condition Requirements to Execute Outcome: All Conditions Are Met (AND)
   1. Row 1:
      1. Resource: {!Get_Public_Group}
      2. Operator: Is Null 
      3. Value: {!$GlobalConstant.False}
5. When to Execute Outcome: If the condition requirements are met.
6. Click Done.

In the end, Donna’s Flow will look like the following screenshot:

Almost there! Once everything looks good, click the Activate button.  

Proof of Concept

1. Create a new User in Salesforce, as shown in the following screenshot:
2. Once you are done, click on the Save button. It will redirect you to a user’s record detail page. Notice that, Permission set group is auto-assigned by the record-triggered flow.
3. Wait a few minutes and then navigate to the Leave Balances tab. A new leave record is created for new hire Ian Young, as shown in the following screenshot:

Formative Assessment:

I want to hear from you!

What is one thing you learned from this post? How do you envision applying this new knowledge in the real world? Feel free to share in the comments below.