A great memory is necessary for violin playing.
Beginners will improve their memory not only by learning music notation, but also by gaining expertise of the instrument. Unlike the piano, the music notes on the violin neck are not clearly defined, so you must remember where they are to play in tune. When you study technical exercises, your muscles will create their own memory.
Furthermore, memorising violin pieces for greater performances will be required. While it is OK to follow the score while performing, playing by heart will increase your sensitivity and, as a result, the beauty of your performance.