On September 1, 2020, we tweaked the way that data element default values are set. Newly created data elements will no longer have a default value set automatically. Today I want to explain what the default values are for, why we're making the change, and explain the specifics of the change.
Data Element Default Value Usage
For the purposes of this conversation, we'll define "data element" to be a pointer to data that will exist inside the client environment at run-time. "Data element value" or simply "value" refers to the actual value that the data element points to or "resolves" to at run-time.
Data elements can be used within events, conditions, actions, extension configurations, and even other data elements. At runtime, the data element is resolved at the time that it is needed. For example, you have a rule with a data element reference inside an action. The rule's event is triggered, the conditions are evaluated, and so now we have to run the action. Launch will resolve the value of the data element, then hand that value to the action so that the action can be run.
If the data element resolves to null or undefined, the first fallback is to a stored value based on the storage duration of the data element. If there is no stored value, then the second fallback is to the default value.
Jim Gordon (of Jimalytics) made this decision flow that describes data element usage. The only change I'd make is to change the word "reset" to "resolve" in the 1st rectangle - and only to make the wording consistent with this article.
Today, the default value for a data element is an empty string (''). It will stay this way unless you provide a different string.
Reason for the Change
The Adobe Experience Edge Network is coming online. We are super excited about it and we want people to check it out. That service requires usage of the Experience Data Model (XDM) which is a defined schema that you use to assign meaning to your data.
Setting an empty string value in your XDM object can cause negative downstream effects. We want to make sure that if you're setting empty strings that you're doing it because you wanted to - not just because that is the default Launch option.
Data elements have a field for a Default Value available in the left rail. Previously, all new data elements were automatically given a Default Value of an empty string (''). If you didn't want that, your other option was to provide a different string.
At the API level, the behavior was similar. The attribute was optional and you were not required to set it. If you provided a value, then Launch will save that value. Otherwise the default value was an empty string. You could not actually save a data element with no default value.
The change we made does not impact the settings or behavior of any existing data elements. It only applies to the automatically assigned default value on newly created data elements.
Instead of automatically assigning an empty string as the default value, Launch will now have no default value.
Once the change is made, if you want your data elements to have a default value, you'll need to select a checkbox labeled "Enable default value". From there, you can:
Leave the field blank to get the old behavior of an empty string
Fill in whatever default value you want
If you leave the checkbox unselected, your data element have no default value.
Previously saved data elements with the empty string will now show in the UI as in the picture above with "Enable default value" selected and no value in the text field.
The API change is similar in nature. The attribute is still optional and you are not required to set it. If you do not provide a value, Launch will now save your data element with no default value - where before it would have been saved with an empty string. If you actually want to save your data element default value as an empty string, you must now provide the attribute and explicitly set it as an empty string ('').
So what does this mean for you? Most probably nothing. All your existing data elements will retain the exact behavior that they have now.
We have also verified that there are no negative affects to your Analytics reports. If you have an eVar or a prop referencing a data element that resolves to null or undefined, these will not show up as "null" or "undefined" strings in your beacons.
The only case where your process may need to change from what you're doing now is if you create a new data element and you specifically need the default value to be an empty string. If this describes you, then in the UI you will have an extra checkbox to select. With the API, you'll need to pass the default_value attribute now, where before you could have left it blank.
This change was made on September 1, 2020. Sound off in the comments below if you have any questions.
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