4_1.sql

to study the example of creation of tables, formative DB, and filling with their information. Using

--alter table Student  
--alter column[id_person]
--int
--NOT NULL

--alter table Student  
--	add constraint check_form check ((id_form=1) or (id_form=2) or(id_form=3) or(id_form=4))

alter table Student  
	add constraint check_form check (id_form between '1' and '5')