First: National Code for Nationalities:
Nationality is the name of the country to which the individual legally belongs, and accordingly issued the individual passport disregarding the place of birth. Accordingly, the individual is said to be Saudi if he/she is born for a Saudi parents or a Saudi father. The non-Saudi is the individual is born for non-Saudi parents. The individual may be naturalized as a Saudi in accordance with the regulations. Non-Saudi citizens who carry more than one pass port their nationalities are determined according to the passport used to enter KSA.
Countries and nationalities are divided in National Code for Nationalities into groups as follows:
(the GCC countries, other Arab League countries, non-Arab Islamic countries, non-Arab non-Islamic Asian countries, non-Arab non-Islamic African countries, EU countries, European non-EU member states, North American countries, South American countries, Oceanian countries, and others) 
Second: Saudi Vocational Classification Guide:
A system to classify professions under unified vocational titles, in addition to providing definitions of such professions that describe the work. These professions are ordered and combined in vocational matrices in series according to the performed work. The profession is given a unique code number to refer to the profession's position in the technical scale of skills.