The University of Anytown School of Business Computing Problem Situation • Student Retention • Too many students enrol on a course then withdraw in their first year • Need a software system to help solve the problem – An improved school intranet Start with a mind map (or rich picture) Develop a Process Map 1. 2. 3. 4. 5. 6. 7. 8. Admissions Pastoral Care Timetabling Module Delivery Peer Tutoring Assessment Attendance Monitoring Research Definition of a Pastoral Services System • A system under the control of an in-school counselling team – giving appropriate referrals to external agencies to students presenting personal problems to members of the counselling team. Root Definition for Peer-Tutoring • A system owned by the school that provides study skills support to students using volunteers from the student body with the quality of their support activities monitored by academic staff Activity Diagram for Peer-Tutoring Peer Tutor Recruitment Sub System Tutee Recruitment Sub System Identify Suitable Peer Tutors Advertise Train Peer Tutors Receive Tutee Document Skills of Peer Tutors Document Tutee Needs Book times and rooms Things that could be added to the activity diagram • Is it enough to advertise? – Should some students be made to attend? • Should we pay peer tutors? – Money? – Credits? • How should the effectiveness of the system be measured? Attendance Monitoring Know tutorial group members Record absentees during a tutorial session Inform pathway leader of persistent absentees Inform student of contact with pathway leader Know student's pathway leader Related Use Cases Print Class List Let’s consider this one Enter Attendance Data for Class Tutorial email pathway leader and student Module Leader Print Attendance Record for Specific Class Print Attendance Record for Specific Student Create Class List The information displayed here might be brought together through collaboration between objects Create Class List Form : Module CreateClassList( ) : Student : Pathway getStudentDetails( ) getPathwayTitle( ) Class Diagram showing relationships between these objects Pathway Title Description registered on 1 get pathway title() n Module Name Module Code Create Class List() Student enrolled on n Name n get student details() We can do two things with this class diagram • Implement it in an OOPL • Translate it into an entity model then implement the entity model as a relational database • CASE tools can help with both of these Three Very Simple Use Cases Create New Supplier Update Supplier Details Delete Supplier Let’s consider some coding issues! One “Entity” Class Three Control Classes Update Supplier Details Create New Supplier Delete Supplier One Boundary Class for all Three Use Cases One Boundary Class One Class to Talk to the Database Sequence Diagram for Supplier Form Control Class Entity Class “Create Supplier” “Supplier” Create New Supplier DB Connection DBSupplier Overview of the System Architecture Project Window for the entire application More Sophisticated Use Cases Perhaps we could ask the Customer object to: – Project future sales to this customer. This would involve analysing past sales to identify trends. Implies the need for a “Customer Sales History” class not currently included in the model. – Collect overdue payments. This would involve generating standard letters to be sent to the customer. Implies collaboration with a “Payment” class (associated with Order or Invoice?) not currently included in the model. Building the Module Maintenance Application in VB Select Add Class Module from the Project menu Use the Class Builder Click the Button to add a new class Give the Class a Decent Name Click the Button to Add an Attribute Give the Attribute a Name and Data Type Select this Button to Add an Operation Name the Operation When we Update the Project the necessary code is generated to implement the class Using a collection to implement a 1:M relationship • We might want to implement a Module class that knows the many pathways on which the module is taught • One of the attributes of this module class will be a collection of pathways! Back to the Class Builder • Assume we’ve created the classes clsModule and clsPathway • We now need to create a class that can manage a collection of pathway objects • Create this collection by clicking this button Use the Collection Builder • To name the collection • And indicate what it is a collection of.. Sequence Diagram • A VB form allows us to select a Module (from a drop down list) and then see a list of the pathways the module is taught on • This involves asking a Module object to ask each of the pathways in its MyPathways collection to display their title. • In UML we document this type of collaboration in a sequence diagram We’ll see how Rational Rose can help • Generate a VB class module from a class diagram • Generate an entity model from the class diagram • Generate a database from the entity model Create a VB6 Model Add a Class Associate the Model with a VB project Generated Program Link to the Rose model Once this connection has been made… • We can.. – Update the VB project from our model – Update our model from the VB project • Round-trip engineering Now for the database.. First tell Rose about the target database Set up a schema for the target database Now generate the entity model Generate the Database from the Schema Example of Generated SQL