In Appian 16.1 and later, when selecting a record in Tempo of an expression-backed record type set to display as a feed, the following error is encountered:
This occurs for newly created record types as well as record types migrated from Appian 7.11 to Appian 16.1 or later.
The behavior for this issue differs between Appian 7.11 and Appian 16.1 and above. In Appian 7.11, only the problematic record itself shows up as an error:
In Appian 16.1 and later, the root cause for this issue is that the expression used to define the record type containing the a!datasubset() function results in an array containing a null element for the field that is defined as the "identifier". The field that is defined as the "identifier" is used to uniquely identify each resulting piece of data within the array.
The example below outlines the "identifier" parameter of the a!dataSubset() function, and shows that the field "ID" is set to uniquely identify each resulting piece of data within the array:
This issue has been addressed via AN-73459 in Appian 17.1 GA. Please upgrade to this version to take advantage of the fix.
The field that is defined as the "identifier", which uniquely defines each resulting piece of data, should not be null. Ensure that your unique identifiers set in this field are a unique value that is not null.
Change the record display from Feed to Grid because the Grid option uses a different expression to create the records which does not appear to error out like the Feed option does.
Change the field in the “identifier” parameter to a different field that could be used to uniquely identify each resulting piece of data.
This article applies to Appian 16.1, 16.2, and 16.3.
Last Reviewed: March 2017
© 2022 Appian. All rights reserved.