Asper School of Business University of Manitoba Systems Analysis & Design Instructor: Bob Travica System sequence diagram Updated: 2014

3510 Systems Analysis & Design * Bob Travica 2 of 12 Outline Concept of SSD Global SSD Creating global SSD Detailed SSD (reading) First cut Full

3510 Systems Analysis & Design * Bob Travica 3 of 12 Concept of System Sequence Diagram (SSD) Part of system design. Communicates to OO programmers. SSD shows interaction between actors and system (global SSD), and among objects (detailed SSD) SSD specifies flow of data (messages) Messages are actions (resemble commands) invoked on destination object

3510 Systems Analysis & Design * Bob Travica 4 of 12 Global SSD SSD of a customer order system Figure 6-14 Content of Item: item details

3510 Systems Analysis & Design * Bob Travica 5 of 12 Global SSD – loops Figure 6-15 True/False Condition Input Expected output Loop Note: extendedPrice = price * quantity

3510 Systems Analysis & Design * Bob Travica 6 of 12 Creating global SSD 1. Start with an activity diagram and/or use case description. 2. Identify the input messages from actor to system. For figuring attributes (input parameters), use class diagram. 3. Identify/apply special conditions (iteration) to input messages, if any. 4. Identify output messages.

7 of 12 Creating global SSD (cont.) Figure Activity diagram of Create New Order use case, Telephone Scenario at RMO Figure Global SSD of the sameFigure 5-31 (detail). Class diagram of RMO Account accountNo customerID Product productID size description Catalog catalogID CatalogProduct price Order orderID accountNo TotalAmt OrderDetail quantity extendedPrice places contains

3510 Systems Analysis & Design * Bob Travica 8 of 12 Detailed SSD Uses the same elements as an SSD Has extra elements: The :System object is replaced by objects and messages within computer system Objects are differentiated (e.g., control handler, domain, user interface) Object activation period indicated

3510 Systems Analysis & Design * Bob Travica 9 of 12 Detailed SSD for Look Up Item Availability - first cut (actor and domain classes) Control handler object Domain objects (replace :System) Activation lifeline Figure 8-14 SSD for Look Up Item Availability use case

3510 Systems Analysis & Design * Bob Travica 10 of 12 Reading detailed SSD (first cut) The system object is broken down to specific objects. Inputs & outputs among objects are specified. Class diagram essential (follow associations).

3510 Systems Analysis & Design * Bob Travica 11 of 12 Adding user interface and database to SSD Add user interface and database objects to domain objects. Example function: Create new student. Additional objects Figure Store database object (record) 4. Update Student record 5. Update Student object 6. Store update

3510 Systems Analysis & Design * Bob Travica 12 of 12 Detailed SSD (final) - reading Reading: Specific catalog and inventory objects are initialized by user’s input, and it will get data from the corresponding database objects. Figure 8-17: Final SSD for the use case Look Up Item Availability (product description, price, quantity in inventory) User Interface Database (DA=Data Access Layer)