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Dispatch

Dispatch events to trigger their handlers. Event data is passed to the handler as typed fields.

Dispatching Events

CREATE NAMESPACE ev_dp;
CREATE TABLE ev_dp::log { action: utf8, item_id: int4 };
CREATE EVENT ev_dp::inventory {
  ItemAdded { item_id: int4 },
  ItemRemoved { item_id: int4 }
};
CREATE HANDLER ev_dp::on_add ON ev_dp::inventory::ItemAdded {
  INSERT ev_dp::log [{ action: 'added', item_id: $item_id }]
};
CREATE HANDLER ev_dp::on_remove ON ev_dp::inventory::ItemRemoved {
  INSERT ev_dp::log [{ action: 'removed', item_id: $item_id }]
};
DISPATCH ev_dp::inventory::ItemAdded { item_id: 42 };
DISPATCH ev_dp::inventory::ItemRemoved { item_id: 7 };
FROM ev_dp::log

Use DISPATCH followed by the event variant and its field values. Multiple handlers can react to the same event.