teaching staff is attached to departments, each staff member belonging to a unique department. (Note: see how many meanings you can assign to this ambiguous sentence). Every course is composed of sub-courses. Some sub-courses are part of more than one course. Staff may teach on many sub-courses and each sub-course may be taught by a number of staff. Draw an entity-relationship model for this example. Show both cardinalities and optionalities. Put a question mark where the degree is not clear from the text. Don't assume anything; rather, write a list of questions you would have to find answers to in order to complete the model.Exercise 3 - SALES LEDGER AND STOCK CONTROLABC Ltd plans to computerize its sales ordering and stock control system. A feasibility study has strongly suggested that a relational database system be installed. The details of ABC's sales and stock control are as follows:Customers send in orders for goods. Each order may contain requests for variable quantities of one or more products from ABC's range. ABC keeps a stock file showing for each product the product details and the preferred supplier, the quantity in stock, the reorder level and other details.
ABC delivers those goods that it has in stock in response to the customer order and an invoice is produced for the dispatched items. Any items that were not in stock are placed on a back order list and these items are usually re-ordered from the preferred supplier. Occasionally items are ordered from alternative sources.In response to the invoices that are sent out to ABC's customers, the customers send in payments. Sometimes a payment will be for one invoice, sometimes for part of an invoice and sometimes for several invoices and part-invoices.Draw an entity-relationship model, stating any assumptions made.What to Hand In:You may use any drawing program you want or do the diagrams by hand andscan them into files to hand in on canvas. If you do use hand drawn scanned files, make sure I can read them.
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- Fall '08
- Entity-relationship model, entity