Tutorial 2 DT228/3 Database Technology

Joe’s Yard Take the following documents: –The script as prepared –The docket –The diary in the yard –The list of new requirements Get the nouns from them. Classify the nouns: –If entities, do they have attributes? –If attributes, do they have values? –If values, what is the attribute?

Start with the script… Joe’s Yard Joe’s builders’ suppliers has a shop and a yard. His system is entirely manual. He has a stock list on the wall of his shop, complete with prices. When a builder wants to buy supplies, he goes into the shop and picks the stock items from the list. He writes his order on a duplicate docket and pays Joe, who stamps the docket as paid. The builder takes the duplicate docket and he goes to the yard and hands it to the yard foreman. The yard foreman gets the ordered items from the yard and gives them to the builder. The builder signs the duplicate docket and leaves one copy with the foreman and takes one copy as a receipt. Every week, Joe looks around the yard to see if any of his stock is running low. He rings up the relevant suppliers and reorders stock. He records the order in his order book, which is kept in the yard. The yard foreman takes delivery of the new stock and checks it against what has been ordered. He pays for it on delivery and staples the receipt into the order book. At the end of every month, Joe goes through all the dockets and the order book and produces a financial report for the shareholders.

Classification of nouns Joe Shop Yard System Stock list Wall Prices Supplies Stock items Docket Foreman Receipt Supplier Order Order book New stock Receipt Month Financial report shareholders Owning entity Irrelevant Entity holding stock info Irrelevant Attribute of stock Entity – Order supplies? Stock info Customer Order External entity or staff member State of the order Entity Physical vessel for entity Supplier Order Attribute of Supplier order State of supplier order Irrelevant Not being considered now Irrelevant

“If you can’t find it, go to Joe!” Joe’s Builders’ Supplies (01) Main St., Malmont, D27. Docket No: 196 Stock code. Quantity Description Unit Price VAT (20%) Total Price A ”x4” treated timber £9.50 £1.30 £45.60 J555 1 Box of 6” phillips screws (100) £5.00 £1.00 £6.00 J501 1 Phillips head screwdriver £8.00 £1.60 £9.60 Total Amount Due: £61.20 Docket paid signature _ Joe Bloggs (Staff) Staff No : 124 Staff Name Joe Bloggs Staff Role : Yard foreman Items received signature__ Andy Handy __(Customer)

The Docket Fields are: –DocketNo, Stock Code, Quantity, Description, UnitPrice, VAT, TotalPrice, TotalAmountDue, DocketPaidSignature, StaffNo, StaffName, StaffRole, CustomerSignature.

The Order Book Fields are: Date, SupplierName, {Stock_Descriptio n}, DateReceived, AmountOwed

Nouns from the Order book 24/9/2004 Buckleys 7 lots of Cavity blocks (100) Received 25/9/2004 Cost €1, /9/2004 Mary O’Brien Stock quantity Stock Item

Set of New Requirements “We want Joe to have a stock level on his stock, so that we know what needs to be ordered.” Two extra pieces of information are required – a current stock level and a reorder level. “We want Joe to know who his customers are, so that he can tout for repeat business.” An extra entity is required to hold customer information and we need to hold docket information for a year. “We want Joe to be able to lodge requested items, so that he can make a decision on whether to stock them in the future or so that he can order them on demand.” Need to record stock requests and the customers who requested them.

Football competition Last week, we started to pick out the entities and attributes for the Football competition case study. Continue with this, and try to build an ERD. Note: –You need not yet resolve many:many relationships.