A State chart shows all the possible states of a class, from the start to the end. In each of the states, the action is also labeled. UML uses state charts to model states and state dependent behaviour for objects and for interactions. A state chart can be seen as a description of all the possible life cycles that an object of a class may follow. It can also be seen as a more detailed view of a class. There is an important link between interaction diagrams and state charts: – the interaction diagrams captures the responses of all the objects, that are involved in a single use case.
– A state chart captures all the possible responses of a single object, to all the use cases in which it is involved. 1. Customer A new customer must be created before any other actions can be carried out. When a customer is created, an estimate can then be requested which then needs to be assessed and sent to either an external surveyor or internal employee. After the estimate is completed, a formal letter will be sent to the customer. If no response is received from customers after five weeks, a reminder letter is sent.
The customer will then send a response detailing their acceptance or rejection. 2. Employee The status of the employees is checked, whether they have been hired or fired. Any newly hired employees will then be added. The employees are then assigned to jobs that are ready. 3. Estimate Either an outside surveyor or a company employee carries out an estimate. The availability of the surveyor/employee is checked. Once they are available, the booking is confirmed and their name is entered onto the booking sheet.
The booking sheet is used to draw up booking letters to send to surveyors confirming the details of the estimate required. The surveyor will produce a report of the completed estimate, which is used for a formal estimate letter to be sent to the customer. If the customer shows acceptance, new jobs would then be created. 4. Job The supplier is contacted for an order to be placed. All the necessary materials will need to be collected in order for the job to be ready to be started. After all the materials have been received, the job begins and the tasks are carried out.
The job progress is monitored and will be completed once all the tasks have been completed. 5. Materials An order line needs to be created for any building material required for a particular task. As the materials arrive, they are collected. When no more material needs to collected, they are sent and the job is ready to begin. 6. Order A new order is created and items are added until no more are required. Once all of the items are added, the order is processed. After the order is submitted, the delivery is awaited from the supplier.
7. Store File A new order must be created. After the materials needed are selected and ordered, they will be stored once received. 8. Supplier The supplier is contacted with new orders, once they receive orders they update their files and finish orders in time for the job to begin. 9. Task A new job is created and then divided into smaller tasks. Once each task is allocated to an appropriately skilled employee, it is begun. The tasks are continued until the job is complete. Database Design
The following is a screenshot of the database relationships screen constructed in Access. It shows the table and link between them. The tables were constructed by taking the UML designs as the basis of the structure of the prototype created to demonstrate the possible format of any future project Ernest Naylor may undertake. Figure 1: Relationships of Tables The following screenshots shows the Employee table and some specimen data that may be found in an Ernest Naylor database. the following is the introductory main menu screen that will be presented in the prototype:
this leads the user to various other screens that can be used to develop the database using an easy to use system interface. These include the entering of new customer details and the requesting of estimates that can be done in an extremely simple method. Also other sections include the ordering of materials for the jobs and also the allocating of tasks to employees and surveyors with a list of who’s available or not in a single screen, which will save the manager the task of providing a list and also increase efficiency in all aspects of the organizations activities.
Some reports were created as a sample of what may be possible bur future investment in a database, that would add extra functionality to your site. As this is only a prototype only a couple of reports were designed that may be of use to Ernest Naylor. Conclusion We hope that this report has developed on your understanding of the system and provided a basis for any further investigation that may be needed before valuable resources are invested in a full working database based on the prototype presented.
For a medium sized construction company, a small database such as the prototype shown can increase overall efficiency and competitiveness in the market place by investing in an electronic storage and retrieval system. Other benefits include; speed of access, minimised duplication of data, user friendly interface, faster processing for your estimation and allocating of tasks, as well as ordering materials. If an expansion of your company was to take place in the following years, the new system would be able to handle any new changes to the administrative tasks without the need for massive changes in the database structure.
Some of the requirements by the employees of Ernest Naylor have been met, however, all have not been implemented as of this time but can be implemented in the future if a greater time frame is allowed to develop the database. This is due to it being a prototype designed to give a demonstration of the future possibilities.
Douglas B. P, (1999). Real-Time UML Second Edition: Developing Efficient Objects for Embedded Systems, Reading, MA: Addison-Wesley; ACM Press. Larman C, (1998).
Applying UM and Patterns: An Introduction to Object-Oriented Analysis and Design, Upper Saddle Ricer, NJ: Prentice Hall. Yourdon E. , (1994). Object-Oriented Systems Design: An Integrated Approach, Eaglewood Cliffs, NJ: Prentice Hall International. Peter Coad, Edward Yourdon, (1993). Object-Oriented Analysis, Prentice Hall International Editions, Second Edition. James Rumaugh, Michael Blaha, William Premerlani, Frederick Eddy, William Lorenson, (1991). Object-Oriented Modeling and Design, Prentice Hall International Editions.