Exam 5: Understanding Entity Relations

In an ERD diagram,primary and foreign keys are shown for each entity type.

In certain cases,adding an additional attribute to and entity can be used in place of a self-referencing relationship.

-Which of the following statements is true?

-If we want to indicate that the authors of a book have conceived it when visiting another author in some country,the symbol used in the Crow's Foot notation would be:

Named relationships are found in both relational database diagrams and ERD notation.

-The following is not a primary key:

-Author-rank-in-book is:

-Which of the following statements is true?

Unary relationships are sometimes called reflexive relationships because they are like a reflection in a mirror.

-The following is a weak entity:

In an ERD,the minimum and maximum __________________ are specified for both directions of a relationship.

An M-way relationship between three entity types is known as a(n)____________ relationship.

In an ERD,a named association among entity types is known as a(n)_____________________.

-If we want to indicate that the authors of a book have conceived it when visiting another author in some country,the usual symbol used in the Chen ERD notation would be:

A(n)______________ relationship is indicated by a minimum cardinality of one or more.

-If we want to indicate that the authors of a book have conceived it when visiting another author in some country,we would use a relationship that would connect:

A relationship that connects two entity types is called a unary relationship.

___________________ occurs when an M-N relationship can be replaced by an associative entity type and two identifying 1-M relationships.

____________________ is a data modeling concept that supports the sharing of attributes between a supertype and a subtype.

-In the ERD shown in 5-2,any RN works: