handleEvent() triggers the statically defined event listener identified by the label parameter. The execution order of the actions defined in the event listener is determined by their seqno property. handleEvent() is typically used for batch execution of related SQL statements as all SQL within one event is executed in one database transaction.
All execution is in a server context. Pure client site actions (such as getValue) are denied with an error message.
Using uwa.groupRequests you can dynamically group actions.
The callback function will cause handleEvent() to operate in asynchronous mode, see executeSQLStatement()