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DATA3

DATA3: TvxClientDataSet

Example​

procedure ScriptEvent(var Value: variant);
begin
  CreateData(DATA3, ['Code,string,40', 'Quantity,integer']);
  DATA3.Append;
  DATA3['Code'].AsString := 'SAMPLE-003';
  DATA3['Quantity'].AsInteger := 3;
  DATA3.Post;
  Value := DATA3.RecordCount;
end;

Usage​

DATA3 provides the third independent action-owned client dataset for general script working data.

Behaviour, errors and limits

  • Record position, fields, schema, filter and index changes affect later code using DATA3 in the same action.
  • Missing fields and invalid edit/cursor state can raise. Velox query helpers normally log and swallow their own exceptions, potentially leaving this dataset inactive.
  • Post records a client-dataset change only; it is not evidence of an external commit.
  • Recreating, loading or querying invalidates retained field/cursor assumptions. Never retain references after a schema change.
  • All query rows are materialised, so large results use memory. Dataset access is mutable and not thread-safe.
  • Load/save and SQL helpers perform their documented external side effects. Never free the action-owned object.

Additional Technical Info​

DATA3 is the third independent TvxClientDataSet supplied as mutable working storage by the current action. It is a live object, not an array element or a predefined VxData table.

The scripter binds it to TvxActionMan.FData3. It begins inactive with no field definitions. Its DATA3 dataset label improves missing-field errors but does not select a connection, command or schema.

Implementation and lifecycle

Population is explicit through CreateData, Data query helpers or load methods. Velox preserves field whitespace, disables auto-calculated fields/fetch-on-demand and requests all rows. Normal SQL opens detach the provider after copying data into memory and disable constraints/change logging. Cleanup closes every action dataset after execution; ownership remains with the action.

Related entries

External references

Created 2026-07-15