根据场景，代画数据库的三种图类型，ER图，DFD图以及Network图。
ER diagram for a system
A football club has a name, a stadium with a playing ground, and a team made up of players. A player can play for only one club. Each team is managed by a manager, represented by his name. A player has a registration number, name and age. A club manager also buys players. Each club plays against each other club in the league and matches have a date, stadium venue and score.
- Draw an ER diagram to represent the case above.
- Discuss how you managed the following:
- What factors were considered for choosing entity, attribute and relationship for the above scenario?
- Is a club manager the same as a team manager?
- How did you represent the ‘league’ in the diagram?
DFD diagram for a system
A system handles purchasing customer tickets for a subway station. The user selects a destination and ticket type (e.g. single, return or day return) and the machine displays the price. When enough money has been put into the slot, the machine issues a date-stamped ticket containing the issuing station, the destination, ticket type and price. If necessary, the machine also gives change. The machine records the number of tickets issued for each destination and the number of tickets of each type for each day. Once a week, these statistics are transferred to the main computer.
- Draw a context diagram (DFD-0) for this system
- Draw DFD-1 diagram for this system
Network diagram
Table 1 shows list of the various activities in a software project development. The third column provides important additional information for coordinating the scheduling of the project members. For any given activity, its immediate predecessors are those activities that must be completed by no later than the starting time of the given activity.
| Activity | Activity Description | Immediate Predecessors | Estimated Duration |
|---|---|---|---|
| A | Stake holder discussions | - | 10 days |
| B | Finalising business requirement | A | 4 weeks |
| C | Requirement specification | B | 10 weeks |
| D | Work Break Down and job allocation | C | 6 weeks |
| E | System specification | C | 20 days |
| F | System design | E | 5 weeks |
| G | Functional Specification | F, D | 7 weeks |
| H | Development specification and development | G | 29 weeks |
| I | Test Plan and Test case | G | 7 weeks |
| J | Unit testing, integrating testing and bug fixing | I | 8 weeks |
| K | System Testing and bug fixing | H, J | 4 weeks |
| L | Acceptance Testing and bug fixing | K | 25 days |
| M | Project documentation | H | 2 weeks |
| N | Client Demonstration and Installation and testing | L,M | 6 weeks |
- Draw a network diagram with duration in weeks.
- Identify the early start, early finish, late start, late finish and slack for each activity in the network diagram (question ‘a’) and tabulate them.
- List one activity from the last that can be delayed, yet not affect the project schedule.
- List one activity which cannot be delayed to finish the project as per schedule. If that activity gets delayed, what corrective measures can be taken to keep the project on track?