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ftLargeint

ftLargeint = 25

Example​

function IsSignedInt64(Field: TField): Boolean;
begin
  Result := Field.DataType = ftLargeint;
end;

Usage​

ftLargeint identifies a signed 64-bit integer field and requires care when crossing Variant, JSON and JavaScript numeric boundaries.

Additional Technical Info​

ftLargeint is declaration ordinal 25 of TFieldType. It identifies signed 64-bit values from -9,223,372,036,854,775,808 through 9,223,372,036,854,775,807.

The full domain is not exactly representable by IEEE-754 Double/JavaScript Number (exact integers end at 2^53-1). When crossing Variant/JSON/Excel/JavaScript boundaries, preserve large identifiers as decimal strings or another agreed 64-bit representation. Validate narrowing and Null separately.

The example only inspects metadata and was source-reviewed; no serialization/conversion/dataset/database/runtime/image test ran.

Created 2026-07-15