[SalesForce] Access index of sObject collection using flow builder loop

I'm using process builder to auto launch a flow. I pass an id to the flow and use the getRecords element to query for a collection of records that returns the records in descending order based on a datetime field. What I'm trying to do is loop over the records and assign the next/previous records into lookup fields that exist on the same sObject.

For example, if I have 5 records, the first record wouldn't have a next__c record, but I would need to grab the 2nd index in the collection to populate the previous__c field of the current record in loop. When I loop over the 2nd iteration in the collection, I would need to access the 1st index of the collection to populate the next__c field value and then the 3rd index of the collection to populate the previous__c field value. Is there a way to access the collection indexes? Or, some other way to accomplish this using flow? Or, do I have to resort to Apex to handle this process?

Best Answer

While in Lightning Flow you can't access record indices in a collection, you can go back to programming techniques first seen in COBOL

As you loop through your fetched records, you will copy at the end of the loop the current record to a separate record variable of the same type (call it previous)

Thus, at the beginning of the loop, you set

previous.Next__c to current.Id
current.Previous__c to previous.Id

At the end of each loop iteration

add previous to a new collection previousUpdates
copy current to previous

You need a decision block to handle the first loop iteration when there is no previous sobject.

Once the loop is exhausted, you update

records // sets all the Previous__c values
previousUpdates // sets all the Next__c values

Related Solutions

[SalesForce] In Flow, how to assign ID field to sobject variables to build sobject collection to Fast Update

This is a limitation of flows. The Id field is contractually read-only, and so the Flow system won't let you assign a value to the Id field. You will need to use a Fast Lookup or Record Lookup to first query the records you want to update. Even though we wouldn't do this in plain Visualforce/Apex Code (since we already have the ID values), Flows do not allow us to simply call into existence records that are already in the database unless we query them somehow. The alternative to this, which I feel defeats the purpose of using flows, would be to create an InvocableMethod and a series of InvocableVariable declarations, and create the objects in Apex Code.

[SalesForce] How to loop a set number of times using visual flow

Unfortunately, the flow Loop element doesn't work that way. The correct method is to build a three-part loop, which has an initialization Assignment, a Decision branch to know when to stop, and an increment Assignment to increase the counter value.

As you can see, step 1 initializes Counter to 0, then we head into a decision where Counter is less than 3. If so, we enter the Loop branch, which does whatever logic you like, then adds 1 to Counter. This repeats until Counter equals 3, at which point it continues to the Continue branch.

The equivalent version of this in Apex Code would be:

for(Integer counter = 0; counter < 3; counter++) {
  // Do logic here
}

Best Answer

Related Solutions

[SalesForce] In Flow, how to assign ID field to sobject variables to build sobject collection to Fast Update

[SalesForce] How to loop a set number of times using visual flow

Related Topic