Dataset FILL events

There are two types of FILL events. One event type is triggered at the dataset level. The other event type is triggered at the level of the temp-table buffer of a dataset. During the FILL operation for a dataset or a temp-table buffer, events are automatically triggered in the AVM. You can write an event handler to execute custom code when a particular FILL event triggers.

Fill events at the dataset level include BEFORE-FILL and AFTER-FILL. They are shown in gray in the following illustration. Fill events at the temp-table buffer of a dataset level include BEFORE-FILL, AFTER-FILL, BEFORE-ROW-FILL and AFTER-ROW-FILL. These events are shown in blue, green, and red in the illustration, and are discussed in the next topic.

The dataset level FILL events, BEFORE-FILL and AFTER-FILL are summarized in the table.

Alternatively, you do not need to use an event to perform these operations. The operations can be performed before or after the call to FILL in your code.

BEFORE-FILL on a dataset

In this example, the BEFORE-FILL event handler prepares the top-level query for the FILL operation.

PROCEDURE preDataSetFill:
  DEFINE INPUT PARAMETER DATASET FOR dsOrderOrderLine.

  /* Load initial data from a JSON file */
  DATASET dsOrderOrderLine:READ-JSON("FILE","Orders.json","EMPTY").
  
END PROCEDURE.

In the internal procedure (preDataSetFill), the dataset is loaded with initial data from a JSON file called Orders.json.

AFTER-FILL on a dataset

In this example, after all the tables are filled the AFTER-FILL event handler detaches the data-sources for all temp-tables in the dataset.

PROCEDURE postDataSetFill:
  DEFINE INPUT PARAMETER DATASET FOR dsOrderOrderLine.
  DEFINE VARIABLE iBuff AS INTEGER NO-UNDO.
  DO iBuff = 1 TO DATASET dsOrderOrderLine:NUM-BUFFERS:
    DATASET dsOrderOrderLine:GET-BUFFER-HANDLE(iBuff):DETACH-DATA-SOURCE().
  END.
END PROCEDURE. /* postDataSetFill */

This procedure uses the NUM-BUFFERS attribute and the GET-BUFFER-HANDLE method to detach all the data-sources in a single procedure call.