The customerID field is a unique area because each customer will have their unique customerID thus the reason for its use as the primary key. The newly introduced tables allow us to have several booked tours associated with a customer thus increasing the flexibility of the system. It also reduces the storage space required. The tour1NF tables are added to allow customers to make several orders (“Informix Guide”, 1998).
A table that keeps tours sold and tour customer data, holds, address, customer name, city, zip code state, tour(s) selected, total amount paid and the number of persons in the tour. Therefore, the structure will be able to show the customer in case he/she books more than once.
Data modelling refers the process of examining data-oriented structures, in that you single out entity types into which attributes are assigned to. The conceptual model can be used to represent the data above.
To make the table2NF compliant we introduce the customerID field as the primary key of the customer table and the foreign key of the newly created table in 1NF tours selected table. This makes the table 2NF compliant.
Using the salesperson table that was described earlier the most appropriate trigger would be a Data Modelling Language (DML) trigger. The trigger is initiated every moment the salesperson sales a tour. In the new data model the customer information is subsidiary to sales information, the trigger is identified as “for each statement type” and is an additional data set for the salesperson each time the tour booking triggers the event.
Using the salesperson table described the appropriate trigger would be a Data Manipulation Language (DML) trigger and would be initiated each time a tour operator sells a new tour. Under the new structure in which the client information is subordinate to sales information, this trigger would be identified as “for each statement type” and would add data set for the ...