drop table test88_pks_person;
drop table test88_pks_employee;
drop table test88_pks_payroll;
drop table test88_pks_project;
drop table test88_pks_address;
drop table test88_pks_contract;
drop table test88_pks_category_contract;
drop table test88_pks_category;
drop table test88_nton_a;
drop table test88_nton_b;
