Chapter 4. Isolating The Domain

Question 1

With a layering approach, any elements of a layer depends only on other elements in __________ or on elements of the layers _________ it.

Answer 1

in the same layer
the layers underneath it

DDD, p. 70

Question 2

What are the four layers in an application?

Answer 2

UI or presentation layer
Application layer
Domain layer or model layer
Infrastructure layer

DDD, p. 70

Question 3

The external user of a system might be a human or ___________.

Answer 3

Another computer system.

DDD, p. 70

Question 4

The application layer ________ tasks and _________ work.

Answer 4

coordinates tasks
delegates work.
If an application needs to send an email, the application layer would request the transmission of the message.

DDD, p. 70

Question 5

The UI layer does two things:
Shows _______ to the user
______ user’s commands

Answer 5

Shows information to the user
Interprets user’s commands

DDD, p. 70

Question 6

The domain/model layer captures what four things about the business?

Answer 6

concepts
information
rules
state

DDD, p. 70

Question 7

The infrastructure layer provides ________ technical capabilities that support ______ layers.

Answer 7

generic
higher
eg. Message sending, persistence, drawing widgets, etc.

DDD, p. 70

Question 8

The grandfather of connecting the UI to the application and domain layers is:

Answer 8

Model-view-controller (MVC)

DDD, p. 73

Question 9

T/F: The infrastructure layer should have knowledge of the domain layer.

Answer 9

False. It contains technical capabilities such a sending an email.

DDD, p. 70

Question 10

Technical capabilities in the infrastructure layer most often offered as ________.

Answer 10

Services.

DDD, p. 73

Question 11

What is another term for domain layer?

Answer 11

The model layer (as in model view controller).

DDD, p. 70

Question 12

DDD pays off best for what type of project?

Answer 12

Ambitious

DDD, p. 76-77

Question 13

What 4 characteristics define the Smart UI anti-pattern?

Answer 13

1. Business logic in the UI
2. Small functions
3. Separate functions in separate UIs
4. Use relational database as shared repository of the data

DDD, p. 77

Question 14

What does 4GL stand for?

Answer 14

Fourth generation language

Mentioned on DDD, p. 77

Question 15

What are the names of some 4GLs?

Answer 15

Cold fusion
Perk, python, ruby
SQL
SAS / SPSS

(from online source)

Question 15

T/F The application layer does not contain business rules.

Answer 15

True

DDD, p.70

Question 16

What is the difference between 3GL and 4GL?

Answer 16

3GL is procedural….you tell the computer how to do something …steps to take. 4GL you tell the computer what results you want (eg, SQL).

(from online source)

Question 17

T/F The application layer cannot contain a state reflecting the progress of a task.

Answer 17

False

DDD, p.70