Strings: Parsing data into other fields in the same table

I am making a simple database and I was wondering how can
the information from a field containing strings of both
numbers and characters be broken and entered other
fields. I am dealing with a code that looks like this:
01MP, and has four parts. The first number refers to the
year 2000, the second number refers the season of the
year (spring), the third to type of media (a magazine),
and the fourth the genre (politics). I have a field for
the code and fields for each of the four parts but I was
wondering how I could automate the entry of the four
extra fields as the data is redundant.