25.1.9.1.4.2 Assigning Participants Dynamically

Assign task participants dynamically with queries, expressions, or functions that return case-sensitive usernames.

To assign task participants dynamically, use a participant Value Type of SQL Query, Function Body, or Expression. When using the SQL Query option, your single column SELECT list returns one case-sensitive username per row. For the Function Body or Expression options, return a comma-separated list of case-sensitive usernames.

Your query, function, or expression can use bind variable syntax to reference task parameter values, action source column names, application items, or other APEX substitution strings.

Tip:

Workflows execute in the background where there is no "logged-in username". So the APP_USER substitution returns nobody in a workflow context. Use APEX$WORKFLOW_INITIATOR to reference the username that initiated the workflow, or APEX$TASK_INITIATOR for the username that initiated the task. If neither of these is the user you need, define a workflow parameter or task parameter to accept a username for other purposes.

For easiest maintainability, your expression can invoke a PL/SQL package function as well. The function can be specific to the task at hand or be generic in nature and accept values like the task ID and task details primary key as PL/SQL IN parameters:

your_app_pkg.owners_for_task(:APEX$TASK_ID, :APEX$TASK_PK)

By passing the value of pre-defined bind variables like APEX$TASK_ID and APEX$TASK_PK, your generic function can lookup related information from APEX dictionary views like APEX_TASKS and from your application table using the primary key value. If needed, you can join in task definition information from the APEX_APPL_TASKDEFS view, using the value of the TASK_DEF_STATIC_ID column in APEX_TASKS.

Caution:

Participant usernames are case-sensitive. If :APP_USER returns DAVID, then use DAVID.