ftMemo

ftMemo = 16

Example

function IsNarrowTextMemo(Field: TField): Boolean;
begin
  Result := Field.DataType = ftMemo;
end;

Usage

ftMemo identifies large narrow text stored through blob infrastructure, with ANSI code-page conversion and whole-value memory risks.

Additional Technical Info

ftMemo is declaration ordinal 16 of TFieldType. It identifies large text in Delphi's traditional narrow memo family. Although logically text, it uses BLOB storage and stream access rather than the ordinary record buffer.

The installed RTL maps it to TMemoField, which descends from TBlobField, enables transliteration and uses ANSI-string behavior on the current Windows build. Unicode assignment can therefore pass through the active code page and lose characters that are not representable. The enum does not record the database character set, line-ending convention, maximum size or collation.

Use ftWideMemo for Unicode large text where the provider supports it. For a current ftMemo, obtain encoding rules from the source schema/driver and normalise line endings only when the integration contract requires it. AsString, AsVariant and byte-array access can load the entire memo; prefer a blob stream for large values.

Null, empty text and a zero-length but non-Null LOB can be distinct. Display conversions may clip or substitute a class description depending on dataset display settings, so display text is not a lossless export path.

The example only inspects metadata and was source-reviewed; no encoding, memo, stream, dataset, database, runtime or image test ran.

External references

• Embarcadero TFieldType and TMemoField.
• Free Pascal TFieldType and TMemoField compatibility references.

Created 2026-07-15