Workflow variables
Workflows typically retrieve, manipulate, and persist data throughout their execution. In Nintex Workflow 2013, a workflow variable is a workflow reference that can temporarily store data for a workflow during run time. For more information about workflow variables, see Nintex Workflow 2013 product documentation.
From a development standpoint, workflow variables are exactly that - variables limited to the scope and context of the running workflow. Unlike other workflow references, such as workflow constants, the values of workflow variables are not persistent.
Supported data types
Internally, workflow variables represent .NET Framework primitive data types and SharePoint 2013 data types. For more information about the data types supported by workflow variables, see Supported data types.
Default values
Default values for workflow variables are stored as association data, included in the workflow association that links the workflow to a SharePoint object. The values stored for workflow variables in association data are used to populate the corresponding activity parameters for the workflow action adapter. For more information about default values in association data, see Using association data for starting workflows.