Section 3 Design
IDENTIFYIND RELATIONSHIPS
What are the three properties that every relationship should have?
Name, optionality, degree
In a business that sells computers, choose the best relationship name from CUSTOMER to ITEM (computer, in this case).
Each CUSTOMER must be the buyer of one or more ITEMS.
Relationships can be either mandatory or optional. True or False?
True
Relationships always exist between
2 entities (or one entity twice)
ER DIAGRAMMING CONVERNTIONS
Attributes are written inside the entity to which they belong. True or False?
True
Entity names are always plural. True or False?
False
Consider the recommended drawing conventions for ERD's.
Indicate which of the following accurately describes diagramming conventions for entities and attributes:
The * means that an attribute is mandatory or required and the entity name should be singular
On an ER diagram which symbol identifies an attribute as part of a unique identifier.
#
Entity boxes are drawn as
Soft Boxes
Which symbol is used to show that a particular attribute is optional?
o
SPEAKING ERDISH AND DRAWING RELATIONSHIPS
Two entities can have one or more relationships between them. True or False?
True
After
looking at the diagram, choose the sentence below that could be "read"
from the existing relationship (even though you're missing relationship
labels!)
Each Student may participate in one or more Activities.
When reading a relationship between 2 entities, the relationship is only read from left to right. True or False?
False
MATRIX DIAGRAMS
Matrix Diagrams helps verify you have identified all possible relationships between your existing entities. True or False?
True
A Matrix Diagram will help you with all of the following except:
Defining Instances of Entities
Creating a Matrix Diagram is mandatory when doing Data Modeling. True or False?
False
sumur : http://quizoracle.blogspot.co.id/2010/11/section-3-design.html
