1. Class diagram II Asper School of Business University of Manitoba Systems Analysis & Design Instructor: Bob Travica Updated: October 2014

2. 3510 Systems Analysis & Design * Bob Travica2 of 9 Outline More on associations & multiplicity Association class Fully developed classes Completing procedure for creation of class diagrams

3. 3510 Systems Analysis & Design * Bob Travica3 of 9 Associations Association types determined by maximum multiplicity (if 2 symbols for multiplicity provided, read that on the right) One-to-one (1:1) - occasional; e.g., Customer—CustomerBillingAddress One-to-many (1:M) - most frequent; for example: Customer—Order (or Customer--SaleTransaction) Many-to-many (M:M) - moderately frequent; examples: Order—Product (or Item), Employee—Project

4. 3510 Systems Analysis & Design * Bob Travica4 of 9 Multiplicity question: Each (one) object on the left side of a relationship can be associated with how many objects on the right side? Then, write the number on right side. - Rule: Usually, the same movie plays in several theatres. Each (one) object on the right side can be associated with how many objects on the left side? Then, right the number on left side. - Rule: Most theaters play several movies in a day. MovieTheatre * MovieTheatre * Multiplicity (more) (1, assumed)

5. 3510 Systems Analysis & Design * Bob Travica5 of 9 Association class* Two ways to think about it: 1) A class that stores some extra attributes that characterize (belong to) the association between classes. 2) Extra storage for data that do not fit into either of associated classes. term

6. 3510 Systems Analysis & Design * Bob Travica6 of 9 RMO CRM system class diagram (simplified) Customary simplification, showing: - Just maximum multiplicity - Just attributes of Association Classes Figure 8-9 modified Catalog Item Order ItemOrder Customer CatalogItem productPrice InventoryItem Shipper **** 1 has * 1 * delivered by *1*1 * * has places delivered by appears on * Shipment * ItemShipment quantity discount Association class contains transaction data. In reading multiplicity neglect association classes! CatalogID ItemID ItemItemNumber ShipmentNum ShipperID OrderNum CustomerID Optional naming of association classes: CatalogDetail, OrderDetail… (Note word “Detail”).

7. 3510 Systems Analysis & Design * Bob Travica7 of 9 Fully developed classes (design level) Methods Attributes - = private + = public () = attribute affected by, input data : string, number = data type Figure 8-7

8. 3510 Systems Analysis & Design * Bob Travica8 of 9 Sources for class diagramming Sources: Description (narrative) Use case diagrams & descriptions Analysis of master data and transactional data

9. 3510 Systems Analysis & Design * Bob Travica Completing a class diagram Standard procedure: 1. List classes 2. List attributes 3. Draw simplified class rectangles (name and attribute segments only) 4. Insert attributes in class rectangles 5. Determine keys 6. Draw associations and name them 7. (New) Draw Association Class for each relationship that has attribute(s) on its own. Note: For now it is important to recognize M:M relationship, not entire multiplicity.