Problem statement and UML building blocks

Problem statement (from the Examination Control Division)

Title: Student Result Management System for the BE programme, IOE.

Present situation: The Examination Control Division (ECD) of IOE receives marks from the examiners and the affiliated campuses (internal assessment and theory/practical marks) on paper or in spreadsheets, enters them manually, calculates totals and grades, prepares mark sheets and publishes results. This is slow, error-prone, hard to verify and hard to update for re-totalling and back papers.

Proposed system: A web-based system to

1. Keep records of students, programmes, semesters, subjects and campuses.
2. Let examiners and campuses submit internal and external marks, with checks and approval.
3. Calculate totals, percentage, grade/division, pass or fail, and back papers automatically.
4. Publish results by roll number, and print mark sheets and transcripts.
5. Support re-totalling, correction and result history.
6. Give reports (pass percentage, rank, campus-wise results).

Users: ECD staff (administrator), examiner, campus exam officer, student. Constraints: secure access, data integrity, backup, heavy load on result day.

Building blocks of UML

UML has three kinds of building blocks.

1. Things

• Structural: class, interface, use case, component, node, collaboration.
• Behavioural: interaction (message), state machine.
• Grouping: package.
• Annotational: note.

 +-----------+  +---------------+     O       ( Publish Result )   +--------+
 | Student   |  | <<interface>> |    /|\                           | note   |
 |-----------|  |   Printable   |    / \                           +--------+
 | rollNo    |  +---------------+   Actor        use case
 | getResult |
 +-----------+
    class          interface

2. Relationships

• Dependency (dashed arrow), Association (solid line), Generalization (solid line with hollow triangle), Realization (dashed line with hollow triangle).

 Student ------- Result     (association)
 Student -|> Person         (generalization)
 Report - - -> Student      (dependency)

3. Diagrams (views of the model)

• Structural: class, object, component, deployment, package.
• Behavioural: use case, sequence, collaboration (communication), state, activity.

Example: for the result system, the class diagram shows Student, Subject, Result; the use case diagram shows the actor ECD Staff with the use case "Publish Result"; the sequence diagram shows getResult(roll) between Student, ResultController and Database.