SQL> recreate table tx(x int not null, y int, constraint y_chk check (x in(1,2,3) and y is not null) );
SQL> insert into tx(x,y) values(null, 100);
Statement failed, SQLSTATE = 23000
validation error for column X, value "*** null ***"
SQL> insert into tx(x,y) values(0, 100);
Statement failed, SQLSTATE = 23000
Operation violates CHECK constraint Y_CHK on view or table TX
-At trigger 'CHECK_11'
SQL> insert into tx(x,y) values(1, 100);
SQL> insert into tx(x,y) values(2, 100);
SQL> insert into tx(x,y) values(3, 100);
SQL> insert into tx(x,y) values(4, 100);
Statement failed, SQLSTATE = 23000
Operation violates CHECK constraint Y_CHK on view or table TX
-At trigger 'CHECK_11'