Rolling Up A Single Record To Its Master Object

Rollup fields are the other of the two types of "calculated value" field allowed in SalesForce.

When you have a "Master-Detail" relationship between two objects in SalesForce, you can add a Rollup Field to the "Master" object that shows the result of an aggregation (count/min/max/etc.) on the values found in a single "column" of the "Detail" object.

But you don't have to use rollup fields exactly as they were intended!

 

Today, I was asked to add a field to "Admissions" called "Application Form Received Date."

After poking around in reports from our legacy system (Banner), I discovered that we calculate this date by looking at the "Received Date" of the checklist item called "Application Form" that is attached to the a given "Admissions" record.

In both Banner and the SalesForce "dumping ground custom objects" for imported Banner data, each application document that we have received is stored in its own record of a "Checklist" object.  "Checklist" is at the "detail" end of a Master-Detail relationship with "Admissions."

It just so happens that in our data model, no "document type" may be used twice in the same set of "Checklist" records.  (Or, in our classic "tines of a garden rake" example, no color of tine may be used more than once on a given rake.)

 

So back to the analogy of children drawing on a garden rake (copying details) as they build it:  the rule here is that if you see an orange tine, you have to copy whatever is doodled on it onto the handle of the rake.

A formula field won't help you implement this rule. Formula fields don't know what to do when they have multiple rows to choose a value from, so they can only copy field values "from handle to tines" (from Master to Detail or from LookedUp to LookingUp).

 

However:

• If you want to copy NUMERIC or DATE data "from tine to handle" (from Detail to Master),
• And you know that you can specify "which color of tine" by inspecting the values of fields on the "tine" (except formula field values),
• And you know that only "1 tine of that color" will exist...

...Then doing a MAX or MIN "Rollup Field" on the "tine" (Detail) field will make an exact copy of it on the "handle" (Master).

 

After all, the solution to "What is the biggest number between 4 and 4?" is ... 4.

 

To build the "Application Form Received Date" field on the "Admissions" object, I added a Rollup Field defined as the maximum "Received Date" among all eligible Checklist items. I then filtered the definition of "eligible Checklist item" to records where "Document Type" = "Application Form" (knowing that there would be only 0 or 1 such records).

 

Yay for kludges! (I think I want to print that and hang it on my wall.)