Multi-User Database Systems

Hatfield Apple Tree Suppliers

Hatfield Apple Tree Suppliers (HATS) sell a wide variety of apple trees of differing varieties. The plants are of different ages and grown on different rootstock types, the rootstock type determines the general size of the tree when mature (see details below). Varieties have different attributes such as colour and size of fruit, at what time of the year they need to be pollinated, when they produce fruit and whether they are a cooking variety, an eating variety or both. All new apple trees are grown by grafting part of an existing variety of tree to a rootstock. This is the only way to maintain the variety. A tree may also be unready to dispatch until a particular date and this needs to be recorded.

The company has become very successful and has moved to a larger site, this means that rather than growing individual trees and recording them with individual identification numbers, it grows batches of trees on the same day grafted from the same variety and rootstock. Customers select trees from the HATS stock batches and can order a quantity of each, as listed on the database. The date and time each order was made should also be recorded, so that they can be serviced in ordered sequence. A customer can select any number of trees without limitation on one order. A customer can also place any number of orders. Customer registration details are held on the database for ease if they re-order in the future. The customer is asked to supply their delivery address, including postcode, phone number and the system records the date they register.

The system is unable to manage stock control at the time of ordering yet, but a query will provide information as to whether enough stock is held to service all requests, so this does not need to be reflected in the E-R diagram.

Additional Information:

· Rootstock:

Types of rootstock on which new apple trees are grafted to produce different sizes of full grown tree, these are specified types as listed below with description of the tree characteristics this rootstock provides (further details at www.rhs.org.uk/advice/profile?pid=359 )

M27 – Extremely dwarfing, height to 1.5m

M9 – Dwarfing, height to 2.7m

M26 – Dwarfing, height to 3.6m

MM106 – Semi-dwarfing, height to 4m

MM111 – Vigorous, height to 4.5m

M25 – Very vigorous, height to 6m

· Each variety has a name and has the following attributes:

· the pollination group: (1 (early) to 8 (late)

· the fruiting season: Early, Mid or Late

· whether the fruit is suitable for cooking, or eating (or both)

· the size of the fruit ( Large, Medium or Small )

· the majority colour of the fruit

· the yield, the amount of apples produced ( Heavy, Average, Light )