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18/2/16.  Aggregation  Part-of relationship between a component or an aggregate (collection) object)

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Presentation on theme: "18/2/16.  Aggregation  Part-of relationship between a component or an aggregate (collection) object)"— Presentation transcript:

1 18/2/16

2  Aggregation  Part-of relationship between a component or an aggregate (collection) object)

3  Composition  Type of aggregation that indicates dependence of one class on the lifecycle of another class StudentSchedule SCHEDULE (PART) is dependent on the lifetime of STUDENT (WHOLE) i.e. if you remove student the schedule is also removed

4  Finding classes is not easy  The more practice you have, the better you get at identifying classes  There is no such thing as the “right set of classes”  Finding classes is an incremental and iterative process

5  Unless you are starting with a lot of domain knowledge, you are probably missing more classes than you will eliminate  Naming a class is also an important activity  The class should describe a single object, so it should be a singular noun or an adjective and a noun

6  Identify the nouns of the description, which serve as the basis for identifying the classes. ◦ Look for out-of-domain nouns (and throw them out!) ◦ Look for abstract nouns (use these for attributes) ◦ The remaining nouns are good candidates “FastData, Inc. employees may order office supplies via the Internal Web and receive a receipt confirming the order. The order must include the user name, user password, account number, and the list of supplies. A receipt must be generated containing an order number, ship date, and total cost. If the order is valid, it must be entered into an order database. If the order is invalid, an error message must be generated.”

7  “….employees may order office supplies via the Internal Web and receive a receipt confirming the order. The order must include the user name, user password, account number, and the list of supplies. A receipt must be generated containing an order number, ship date, and total cost. If the order is valid, it must be entered into an order database. If the order is invalid, an error message must be generated.”

8  Out-of-Domain ◦ Internal Web  Abstract ◦ user name ◦ user password ◦ account number ◦ order number ◦ ship date ◦ total cost ◦ list of supplies ◦ office supplies -> item  Good Candidates ◦ employee ◦ item (was office supplies) ◦ receipt ◦ order ◦ order database ◦ error message  Notes Decided not to worry about the Web in this design. Instead we focus on the inputs outputs.

9 order DBemployee name password order number account total cost receipt order number ship date total cost item name quantity price error message explanation

10  Postgraduate admission  Look at ◦ How to collect requirements  One business process ◦ How to do analysis  Including dynamic diagrams ◦ How to make design decisions  transform analysis diagrams to design ones

11  Postgraduate admissions ◦ UCC has its undergraduate admissions automated through the CA0 website ◦ The site is still not fully functional for post-grad applications ◦ Although CAO will include PG applications for the whole country and abroad in the near future, UCC wishes to have an online solution in the interim

12  Investigating current system for undergraduates  Site visit at registrars office  Interviews ◦ with registrar ◦ with current PG students (who applied last year)

13  The college processes applications for its postgraduate courses from home graduates and graduates from other institutions.  Interested students may get an application from the registrar office (in person or via post) or download one from the website.  Once the filled-in application form arrives, the admissions section records the date of receipt of all applications in the applications book.  Before proceeding the form is checked for potential errors ◦ Fields omitted, inappropriate information, missing signature etc.  Home graduates are accepted if they meet the entry requirements ◦ Checked against lists of degrees ◦ Check previous examination results by the records section  Other outside graduates are rejected if they don’t meet the entry requirements, and even if they do, a reference is sought ◦ If the reference is satisfactory, the graduate is accepted.  All applicants receive a letter from the college advising them if they’ve been accepted or rejected, and the date that this is sent is recorded in the applications book.

14 APPLICATION PROCESSING SYSTEM PROCESSES/ACTIVITIES & DATA APPLICANT RECORDS OFFICE REFEREE Main user: ADMISSIONS OFFICER CAO (other universities)


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