firedac数据集数据序列为JSON

procedure TForm1.Button1Click(Sender: TObject);
begin
  var ss: TStringStream := TStringStream.Create(‘‘, TEncoding.UTF8);
  FDQuery1.SaveToStream(ss, sfJSON);
  Memo1.Text := ss.DataString;
  ss.Free;
end;

{
    "FDBS":
	{"Version":15,
	    "Manager":
		{"UpdatesRegistry":true,
		    "TableList":
			[
				{"class":"Table","Name":"FDQuery1","SourceName":"tunit","SourceID":1,"TabID":0,"EnforceConstraints":false,"MinimumCapacity":50,
				"ColumnList":
				[
					{"class":"Column","Name":"unitid","SourceName":"unitid","SourceID":1,"DataType":"AnsiString","Size":4,"Searchable":true,"Base":true,"OInUpdate":true,"OInWhere":true,"OInKey":true,"OriginColName":"unitid","SourcePrecision":4,"SourceSize":4
					},
					{"class":"Column","Name":"unitname","SourceName":"unitname","SourceID":2,"DataType":"AnsiString","Size":6,"Searchable":true,"AllowNull":true,"Base":true,"OAllowNull":true,"OInUpdate":true,"OInWhere":true,"OriginColName":"unitname","SourcePrecision":6,"SourceSize":6
					}
				],"ConstraintList":[],"ViewList":[],
				    "RowList":
					[{"RowID":0,"Original":{"unitid":"11","unitname":"个"}},{"RowID":1,"Original":{"unitid":"12","unitname":"双"}}
					]
				}
			],"RelationList":[],"UpdatesJournal":{"Changes":[]}
        }
    }
}