Final Exam Part I Flashcards

Question

Explain what ‘includes’ and ‘extends’ relationships are in use cases.

Answer 1

Includes: the relationship is mandatory Extends: the relationship is optional

Answer 2

A Kanban is a board for user stories that easily allows for developers to update the stories as they move through the development process. These boards usually consist of backlog, todo, doing, done, and accepted. Where each story will move through the board until it is either discarded or completed. While they were originally made of whiteboards and post it notes, we now have modern Kanban like Trello, and Waffle.

Answer 3

Pros: + Avoid user typos – good for reports! Cons: - Less flexible -> the user cannot create new categories - Susceptible to programmer typos if the value appears in several places (Should only be used if the value will never change)

Answer 4

When you: + Desire less typos and option-specific operations. + Have automated deployment. + Have easy access to your development team. Example: Users have the option of choosing one type of card: Club, Diamond, Heart, or Spade. Enumeration would make the choice much easier than defining four different types of card through associated classes.

Answer 5

An associated class is used when you want to give the user the control to add options or change certain things. It is better to use inheritance when everything that you want is predefined; the developer simply decides where to place a category in the inheritance tree. ``` Example: A Convertible, a Lamborghini, and a Sedan are all Cars. If the class Car were defined with a variable for speed, a variable for color, and a variable for number of doors, it would make sense that the Convertible, Lamborghini and Sedan inherited from the class Car so that each (sub)class would also have all of the variables specific to the class Car without those variables having to be unnecessarily redefined - as would be the case with the creation of associated classes. ```

Answer 6

Associated inheritance would give the user the ability to add a child class that did not already exist, which is good if the developers wanted to give users more control. In the event that the developers did not want the user to have much control, one would use "basic" inheritance. ``` Ex: If there was a class--Snack--that the user could access, but all subclasses of the class Snack (Chip, Cookie, Fruit) were not the class that the user desired, an associated inheritance would allow the user to create the subclass of Snack that they wanted to include (Brownie). However, if there were only so many Snacks that were available to the user and only those snacks, a “basic” inheritance would ensure that the user could not make a subclass of Snack that would have no place in the program; only three different subclasses of Snack are allowed and no more. ```

Answer 7

Perhaps we could change the association between Account and AccountType. Instead we could use an inherited association so each subclass can inherit from the AccountType. This will allow the financial director to create new AccountType subclasses as he sees fit. The federal laws could be an extension of AccountType so that all inherited subclasses can see the desired methods.

Answer 8

As Data: + Possible values can be managed by the user (more flexible) As Source Code Elements: + Need to change the implementation every time the possible values change (recompile & redeployment) Example: Say a system has different types of accounts. Making the account type an attribute of the account class is a data representation, as the type can easily be changed by a simple setter method. Creating a new account type is just as easy. If the account types are represented as their own sub-classes of a general Account class, this is a source code element representation. In order to add a new account type, a new subclass needs to be created. This requires the system to be recompiled with this new class now included. In order to change the account type in this representation, the account must be recreated, transferring the attributes of the old class to the new one.

Answer 9

Redundant connections can be taken out and the model will still makes sense. Example: Students are associated with many sections that contain a course. Students are are also in many courses. This is redundant, we could take out the Student class' many-to-many association with the Course class and this would still make sense. The same goes for the professor class, if the professor has many sections he teaches, this implies that each section has a course. So we can erase both connections to the course. and route both classes through the Section class for the same effect.

Answer 10

+ Whenever the user has some sort of interaction with the elements of the system. + Usually denoted by a name of the action over the link between the user and the system element.

Answer 11

You can make the associated connection many to many (*-----*) for a simple solution. Example: [Passenger]*-------1[Bus] => [Passenger]*-------*[Bus] ``` Other ways to register history of associations: + Add a data attribute to “Client” containing an array of client's previous addresses + Associate the client class with an address class (make associated connection one to many (1--------*)) ```

Answer 12

+ Storing derived data is faster reading + There is no calculation and values are simply accessed + Stored derived data simplifies database queries; this is important for complex analytical queries

Answer 13

A property which values are produced or computed from other information, for example, by using values of other properties.

Final Exam Part I Flashcards

(37 cards)