It should be on PL/SQL

a. prepare a receipt for the service

b. calculate salary for all employees (based on the fulfilled services);

c. One of the hairdressers is sick. For each of the services assigned to him or her find a replacement - first we should look for those hairdressers that have a shift scheduled for that day.

tables

CREATE TABLE Customers ( CustomerID integer NOT NULL, NameSurname varchar2(50) NOT NULL, PhoneNumber integer NOT NULL, Discount integer NOT NULL, CONSTRAINT Customers_pk PRIMARY KEY (CustomerID) ) ;

CREATE TABLE Reservations ( ReservationID integer NOT NULL, ReservationDate date NOT NULL, Paid number(6,2) NULL, ReceiptNO integer NULL, CustomerID integer NULL, EmployeeID integer NULL, ServiceID integer NOT NULL, CONSTRAINT Reservations_pk PRIMARY KEY (ReservationID) ) ;

CREATE TABLE Services ( ServiceID integer NOT NULL, ServiceName varchar2(100) NOT NULL, Fees number(6,2) NOT NULL, CONSTRAINT Services_pk PRIMARY KEY (ServiceID) ) ;