Velox

DEvent and DIssue are live pointers used by the standard Velox scriptlet's event/issue workflow. They do not create, configure or query a dataview. The action fields begin nil; the scriptlet's Initialise(aDIssue, aDEvent) procedure assigns the supplied TdaSQLQueryDataView objects.

Required initialisation

Call the governed initialisation path with the issue and event dataviews that belong to the current transaction/map contract before any helper expects these variables. Always guard nil, and also confirm that the supplied view is in the state required by the class/member you call. A non-nil pointer does not prove an active query, current row or valid schema.

Shared object state

Each variable aliases the exact supplied dataview. Cursor movement, filters, parameters, SQL/query state, edits and close/open operations are visible through every other reference to that object. Velox does not join issue/event rows, select a connection, create a row or persist an edit merely because the pointer is assigned.

The action's data reset sets both pointers to nil. Scripts do not own the views and must never free them or retain them beyond the owning map/action context. The mutable views are not safe for asynchronous or concurrent use.

Compatibility behaviour

Deprecated InitialiseInterchange assigns interchange issue/event views to these current pointers. Deprecated InitialiseIssue can reassign DIssue, and passing nil makes it fall back to DInterchangeIssue. Legacy scripts can therefore change which issue view later functions observe. New work should use Initialise(Issue, Event) and transaction-specific issue/event configuration.

Safety and business meaning

An issue/event dataview row is configured data, not automatic proof that a notification was sent, a transaction failed/succeeded, a database commit occurred or an audit event is complete. Validate required fields and keys, distinguish current-row state from persisted state, and use the documented function that performs the intended effect.

Created 2026-07-19