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FieldByIndex

function FieldByIndex(const FieldIndex: Integer): TvxField;

Example​

function FirstFieldText(const View: TdaCDSQueryDataView): string;
begin
  Result := View.FieldByIndex(0).AsString;
end;

Usage​

FieldByIndex returns the zero-based field-list entry from the client dataset; ordering is metadata-dependent and an invalid index raises.

  • Prefer FieldByName for stable mapping logic.
  • Use index access only when the exact DataView field order is part of the governed configuration.
  • Do not retain the reference after the dataset closes/recreates its fields.

Additional Technical Info​

FieldByIndex returns one TField object from the concrete view's client dataset. PascalScript exposes the return as TvxField, an API overlay over the actual native field descendant.

Source-backed behaviour​

The hidden base returns nil. Both shipped descendants override it with FQuery.Fields[FieldIndex]. The index is zero-based collection order. Delphi's field list checks the range and raises for negative or >= FieldCount; the method does not return nil for an invalid index.

Field order is configured/generated metadata and can be changed through TField.Index; it is not a stable database ordinal. For file/CDS views, generated ID and MASTER_ID fields occupy important early positions, and Insert relies on indexes 0/1. The returned object remains owned by the dataset and must not be freed.

Official terminal references​

Created 2026-07-15