create table employees(employee_id char(5) PRIMARY KEY,first_name varchar2(10) NOT NULL,last_name varchar2(10) NOT NULL,email varchar2(30) NOT NULL,phone_number varchar2(15) NOT NULL,hire_date DATE NOT NULL,job_id varchar2(10) NOT NULL,salary varchar2(20) NOT NULL,commision_pct varchar2(20),manager_id char(8) NOT NULL,departement_id char(8) NOT NULL,);insert into employees values ('101','adhitya','alam','aalam','515.123.455','17-JuN-90','aa_press','2500',)insert into employees values ('102','danar','adi','dadi','515.123.456','08-FEB-87','da_press','2900')insert into employees values ('103','victor','wooten','vwooten','515.123.457','12-APR-95','vw_press','2750')insert into employees values ('104','jaco','pasto','jpasto','515.123.458','08-FEB-77','jp_press','3500')declarev_fname varchar2(20);beginselect first_name into employees where employee_id=100;end;/create table departement(departement_id char(5) PRIMARY KEY,departement_name char(15) NOT NULL,manager_id varchar2(5) NOT NULL,location_id varchar2(5) NOT NULL);insert into departement values ('10','administration','200','1700');insert into departement values ('20','marketing','210','1800');insert into departement values ('50','shipping','124','1500');insert into departement values ('60','it','103','1400');insert into departement values ('80','sales','149','2500');insert into departement values ('90','executive','100','1700');insert into departement values ('110','accounting','205','1700');insert into departement values ('190','contracting','200','1700');create table job_grade(gra char(5) PRIMARY KEY,lowest_sal int(15) NOT NULL,highest_sal int(5) NOT NULL,);