5370 Quiz 4
Referring to the figure below, which of the following is NOT true?
A component is always used in only one item.
In the figure below, what is depicted?
An associative entity
In the figure below, Customer_ID in the CUSTOMER Table is which type of key?
Candidate
In the figure below, the primary key for "Order Line" is which type of key?
Composite
A composite key consists of only one attribute.
False
A synonym is an attribute that may have more than one meaning.
False
A transversal dependency is a functional dependency between two or more nonkey attributes.
False
CASE tools can model more complex data relationships, such as ternary relationships.
False
Data integrity consists of powerful operations to manipulate data stored in relations.
False
The entity integrity rule states that a primary key attribute can be null.
False
The primary key of the many side migrates to the one side when transforming a one-to-many relationship.
False
The relational data model does, at this time, directly support subtype/supertype relationships.
False
Which of the following are properties of relations?
No two rows in a relation are identical.
A cascading delete removes all records in other tables associated with the record to be deleted.
True
A primary key is an attribute that uniquely identifies each row in a relation.
True
A referential integrity constraint is a rule that maintains consistency among the rows of two relations.
True
A relation in fifth normal form may not contain any anomalities.
True
In the figure below, each employee has exactly one manager.
True
One property of a relation is that each attribute within a relation has a unique name.
True
Sample data are useful for developing prototype applications and for testing queries.
True
The allowable range of values for a given attribute is part of the domain constraint.
True
View integration is the process of merging relations together.
True
A primary key whose value is unique across all relations is called a(n):
enterprise key.
A constraint between two attributes is called a(n):
functional dependency.
An attribute that may have more than one meaning is called:
homonym.
A form of database design which maps conceptual requirements is called:
logical designs.
Understanding the steps involved in transforming EER diagrams into relations is important because:
one must be able to check the output of a CASE tool.
A functional dependency in which one or more nonkey attributes are functionally dependent on part, but not all, of the primary key is called a _____ dependency.
partial functional
A rule that states that each foreign key value must attach a primary key value in the other relation is called the:
referential integrity constraint.
A relation that contains minimal redundancy and allows easy use is considered to be:
well-structured.