procedure to add new customer invoice addInvoice(customername, employeeName, branchName, invoice_date) then the procedure will check from the exists of customername, employeeName, BranchName by calling there check existsing function for each name and if all of them are exists then a new record will be created with total price equel to zero and the invoceno will be generated using method getNextInvoiceNo() which return the maximum +1, then the method will display the message" one record has been created with invoice No:show the generated invoiceNo her in this message " else display a specific message that show the customer or employee or branch name doesn't exist please re-enter correct names. tables: Items (itemNo, ItemName, Price, total_quantity, catNo), Items_stor_entry(entry_no number primary key,itemNo, entry_date , quantity), Employee (employeeNo, employeeName, job) , branch(No, Name), Customer (customerNo, costomerName, gender), , Invoice (employeeNo, customerNo, total price, invoiceNo, InvoiceDate, branchNo )