Database systems-Entity-Relationship modelling Essay

Database systems-Entity-Relationship modelling - Essay Example A database will help to make the report generation process faster with the use of correct report generating programs. The management will have the option of having up-to-date information when it comes to decision making in Lanchester Liners. Since all the data is retrieved from a central database, the consistency of the data is guaranteed. It becomes a clear advantage of a database, since the manual file systems are vulnerable to duplicated data. The security of data can also be enhanced with the implementation of a database using passwords and other security protocols. For this company, a computerized database will make the data available to remote locations such as to a ship in the middle of a journey by the using modern communication technology. The transition from a manual file system to a database system will make the company concentrate on staff training, spending on hardware and software. The company also has employee new team of professional to maintain the technical aspects of the database. These two factors can be considered as the drawback occurring from the implementation of a database. The Business rules of the system Following Business rules have been identified according to the interview conducted with Lanchester Liners Company. 1. ... 4. Many employees are assigned to ship at a time and an employee works in a one particular ship at a time. 5. A passenger may book several excursions and a particular excursion may be booked by several passengers. 6. A Passenger may be in many cruises from time to time. A cruise takes many passengers. 7. An itinerary consists of several excursions and an itinerary may share several excursions. 8. Excursion consists of many attractions. An attraction is limited to only one excursion. 9. Some passengers may also do lecture to other passengers. ER – Model of Lanchester Liners Primary key - Foreign key - Non-prime attributes – In Red The list of Entities, Attributes, and Relationships of the system Entity Attributes Primary Key Foreign keys SHIP Ship _No - Ship Number Ship _Name Ship _No ------------- ITINERARY It_ID - Itinerary ID It_ID Sh _It * Dep _Port – Departing port Arri _Port – Arriving port Ship _No - Ship Number It_ID - Itinerary ID Ship _No It_ID Sh ip _No It_ID CRUISE Cruise_ID – Cruise ID Days of tour – Week days of the tour Tour _Operator – Tour operator’s name Cruise_ID ------------- Cr _It * Cruise_ID It_ID Cruise_ID It_ID Cruise_ID It_ID PASSENGER Pas_ID – Passenger ID Pas_Contact – Passenger contact details Pas_Name – Passenger Name Pas_ID ------------- P Assigned to Cruise_ID Pas_ID Pas_satis – Passenger satisfaction Cruise_ID Pas_ID Cruise_ID Pas_ID EXCURSION Exc_ID – Excursion ID Exc_ID -------------- Booking Exc_ID Pas_ID Exc_ID Pas_ID Exc_ID Pas_ID ATTRACTION Att ­_ID – Attraction ID Att_desc - Attraction Description Exc_ID Att ­_ID Exc_ID It _Ex * Exc_ID port_name It_ID It_ID Exc_ID It_ID Exc_ID EMPLOYEE ** Emp_Name - Employee Name Emp_ID - Employee ID Emp_phn –