Am just wondering about what trigger/type/condition to take.
To me trigger names are not always self-explanatory.
Is there a list just briefly describing what's behind all those triggers?
Not really. We've the below, but it just lists the trigger usage it self with its variables. All newer triggers should be self explanatory though. The trigger used is entirely dependent on what you intend to do in most cases though so even if a trigger had a description it could be completely irrelevant to the usecase.
www.joomlapolis.com/documentation/279-community-builder/tutorials/18358-using-cb-triggers
As CB QUERY field type has no built-in option "update on" I assume am expected to define an AJAX auto action to do the job.
Update is specific to one single field. I am afraid not to know what combo of trigger/type/condition to choose. And to assign the correct field which triggers.
The trigger for ajax responses for a field is onBeforefieldClass and onAfteronBeforefieldClass. Your ajax would need to call the fieldClass URL for the query field which you'd need to act on in CB Auto Actions to give your ajax a response. For that to work you'd need to also send the value of the field that was changed and that is triggering the Update On and then modify the user object in your response code so the query field will appropriately update. I really don't see this happening though as it's an extremely advanced usecase. There is zero documentation for such a case. At any rate your ajax endpoint URL would be as follows.
index.php?option=com_comprofiler&view=fieldclass&function=updateon&user=USER_ID_HERE&field=FIELD_NAME_HERE&reason=edit&format=raw
Your code should specifically check that function updateon was specified in the GET variables as the endpoint URL calls a singular function for a field, which could have other ajax functionality.
krileon
