[Error] Unit3.pas(322): Undeclared identifier: 'FieldTypeToString'

对不起，我之前给出的代码示例中使用了一个自定义函数FieldTypeToString，但是我没有提供该函数的实现。请将以下代码添加到你的Unit3.pas文件中，以解决"Undeclared identifier: 'FieldTypeToString'"错误：

function FieldTypeToString(fieldType: TFieldType): string;
begin
  case fieldType of
    ftString: Result := 'String';
    ftSmallint: Result := 'Smallint';
    ftInteger: Result := 'Integer';
    ftWord: Result := 'Word';
    ftBoolean: Result := 'Boolean';
    ftFloat: Result := 'Float';
    ftCurrency: Result := 'Currency';
    ftBCD: Result := 'BCD';
    ftDate: Result := 'Date';
    ftTime: Result := 'Time';
    ftDateTime: Result := 'DateTime';
    ftBytes: Result := 'Bytes';
    ftVarBytes: Result := 'VarBytes';
    ftAutoInc: Result := 'AutoInc';
    ftBlob: Result := 'Blob';
    ftMemo: Result := 'Memo';
    ftGraphic: Result := 'Graphic';
    ftFmtMemo: Result := 'FmtMemo';
    ftParadoxOle: Result := 'ParadoxOle';
    ftDBaseOle: Result := 'DBaseOle';
    ftTypedBinary: Result := 'TypedBinary';
    ftCursor: Result := 'Cursor';
    ftFixedChar: Result := 'FixedChar';
    ftWideString: Result := 'WideString';
    ftLargeint: Result := 'Largeint';
    ftADT: Result := 'ADT';
    ftArray: Result := 'Array';
    ftReference: Result := 'Reference';
    ftDataSet: Result := 'DataSet';
    ftOraBlob: Result := 'OraBlob';
    ftOraClob: Result := 'OraClob';
    ftVariant: Result := 'Variant';
    ftInterface: Result := 'Interface';
    ftIDispatch: Result := 'IDispatch';
    ftGuid: Result := 'Guid';
    ftTimeStamp: Result := 'TimeStamp';
    ftFMTBcd: Result := 'FMTBcd';
    ftFixedWideChar: Result := 'FixedWideChar';
    ftWideMemo: Result := 'WideMemo';
    ftOraTimeStamp: Result := 'OraTimeStamp';
    ftOraInterval: Result := 'OraInterval';
    ftLongWord: Result := 'LongWord';
    ftShortint: Result := 'Shortint';
    ftByte: Result := 'Byte';
    ftExtended: Result := 'Extended';
    ftConnection: Result := 'Connection';
    ftParams: Result := 'Params';
    ftStream: Result := 'Stream';
    ftTimeStampOffset: Result := 'TimeStampOffset';
    ftObject: Result := 'Object';
  else
    Result := 'Unknown';
  end;
end;

这段代码将根据TFieldType枚举值返回相应的字段类型字符串。请确保添加了这个函数后重新编译你的代码。

希望这次能够解决问题！如果还有其他问题，请随时提问。