Pacifica Computer Solutions (PCS) is in the business of selling complete computer systems (desktop PC) at much reasonable prices compared to their competitors. First PCS purchases computer parts from various local and overseas suppliers. The technicians at PCS then use these parts to assemble computer systems. In addition to selling the assembled computer systems to its customers, PCS also sells the computer parts as well.

Currently there is no computerized information system and all records of company transaction and stock list of parts are kept manually. The inefficiency in the manual system is creating a lot of problems for PCS. In particular the list of parts at hand does not get updated promptly whenever parts are sold to customers. Thus if supply of a part runs low there is no early warning system and in the worst case if the supply of any part runs out it is impossible to assemble the computer system.

The manager of PCS has approached InfoTech, an information system development firm where you are employed as a systems analyst. PCS wishes to acquire an information system to computerize its operations. During interview the manager describes the current operations of PCS as well as the features he would like to see in the new system. The following outlines results of the interview.

All items (parts or computer systems) sold by PCS come with one year warranty. Customers can buy items only on cash. At the counter the salesperson enters the following details about new customers for warranty purposes: customer ID, customer name, phone number, postal address. For the items sold the salesperson records the following for each item: Item number and quantity sold. The proposed system should print invoice which provides the customer details, item details (Item number, name, description, quantity sold, and unit price), date of sale and total amount payable by the customer. After the sale is finalized the system should update the quantity of each item at hand.

The primary responsibilities of the technician are to assemble computer systems and repair items under warranty. Before a technician begins her/his work s/he creates a job sheet which records Item number, Item name and serial number of parts that the technician has removed from storage in order to complete the job. In addition to this the job sheet also records date & time of job commencement and completion.

The proposed system should automatically update the quantity of each part at hand whenever a job sheet is created reflecting parts removed from storage. When a job involving assembly of a computer system is complete the computer system is assigned an Item number and the list of available computer systems in stock is updated.

For each computer part the manager specifies a threshold level, which is the minimum number of particular part needed for smooth operations. If the system detects that the actual number of parts at hand is less than the threshold then the system should produce a report alerting the manager to this effect. The report should give details about the part which is running low in stock together with the threshold level and actual stock level. On the basis of this report the manager can order parts from his suppliers. Once the parts have been supplied the details of these parts are entered into the system thereby updating the stock levels.

Periodically the manager would like to review the list of suppliers maintained by the Information system. If the supplier gets out of business or is no longer able to supply the parts on time then the manager removes the supplier from the system. On the other hand if a new supplier selling computer parts at a cheaper rate is discovered then the following details of the supplier are recorded by the manager: Supplier name, address and phone contact.

The manager requires monthly sales and purchases report which he uses to formulate marketing strategies. In addition to this the manager requires productivity report on technicians so as to decide on the incentive packages.

The productivity report is based on information from the job sheets created by the technicians. In order to produce this report the manager provides the name of the technician, the systems then refers to the job sheets in order to calculate the number of jobs done in the current month and average time to complete job. The productivity statistics of the technicians is then sent to the standard printer.

Task:

Make an event table and Entity Relationship diagram from the above the case study

Sol82:

Event table:

Event	Trigger	Use Case
Customer purchase	Salesperson enters item details and customer information	Create Invoice, Update Stock
Job sheet creation	Technician creates job sheet	Update Part Quantity
Computer system assembly	Technician completes assembly job	Update Stock
Low stock alert	Actual stock level is less than threshold level	Generate Low Stock Report
New supplier discovered	Manager discovers new supplier	Add Supplier Information
Monthly report request	Manager requests monthly sales and productivity report	Generate Sales and Productivity Report