[cecam]

Como bien comenta rhino0nt en la bdd se define como TINYINT(1).

Después en el Delphi, usamos Zeos, y en la unit ZAbstractRODataset tengo una pequeña modificación en la siguiente función:

procedure TZAbstractRODataset.InternalInitFieldDefs;
var
  I, J, Size: Integer;
  AutoInit: Boolean;
  FieldType: TFieldType;
  ResultSet: IZResultSet;
  FieldName: string;
  FName: string;
begin
  FieldDefs.Clear;
  ResultSet := Self.ResultSet;
  AutoInit := ResultSet = nil;

  try
    { Opens an internal result set if query is closed. }
    if AutoInit then
    begin
      CheckSQLQuery;
      CheckConnected;
      ResultSet := CreateResultSet(FSQL.Statements[0].SQL, 0);
    end;
    if not Assigned(ResultSet) then
      raise Exception.Create(SCanNotOpenResultSet);

    { Reads metadata from resultset. }

    with ResultSet.GetMetadata do
    begin
      if GetColumnCount > 0 then for I := 1 to GetColumnCount do
      begin
        FieldType := ConvertDbcToDatasetType(GetColumnType(I));

        if FieldType in [ftString, ftWidestring, ftBytes] then
          Size := GetPrecision(I)
        else Size := 0;

        //TinyInt(1)= SmallInt = Boolean
        if  (   (FieldType=ftSmallInt)
             or (FieldType=ftInteger)
             or (FieldType=ftLargeint)
            )
        and (GetPrecision(I)=1)
        then FieldType:=ftBoolean;
        //TinyInt(1)= SmallInt = Boolean

        J := 0;
        FieldName := GetColumnLabel(I);
        FName := FieldName;
        while FieldDefs.IndexOf(FName) >= 0 do
        begin
          Inc(J);
          FName := Format('%s_%d', [FieldName, J]);
        end;

        with TFieldDef.Create(FieldDefs, FName, FieldType,
          Size, False, I) do
        begin
          {$IFNDEF FPC}
{$IFNDEF FOSNOMETA}
          Required := IsWritable(I) and (IsNullable(I) = ntNoNulls);
{$ENDIF}
          {$ENDIF}
{$IFNDEF FOSNOMETA}
          if IsReadOnly(I) then Attributes := Attributes + [faReadonly];
          Precision := GetPrecision(I);
{$ENDIF}
          DisplayName := FName;
        end;
      end;
    end;

  finally
    { Closes localy opened resultset. }
    if AutoInit then
    begin
      if ResultSet <> nil then
      begin
        ResultSet.Close;
        ResultSet := nil;
      end;
      if Statement <> nil then
      begin
        Statement.Close;
        Statement := nil;
      end;
    end;
  end;
end;

Recompilamos las Zeos, y ya podemos usar los Tinyint(1) como si fueran ftBoolean, incluso en diseño.

Saludos!!