DBMS Chapter 4 Review

An ERM is dependent on the database type.

The word "entity" in the ER model corresponds to a table.

The Crow's Foot model is less implementation-oriented than the Chen model.

The ER diagram represents the conceptual database as viewed by the end user.

The ER model refers to a specific table row as an entity instance.

In both the Chen and Crow's Foot models, an entity is represented with a rectangle containing the entity's name.

The ER model refers to a specific table row as an entity occurrence.

Attributes are types of entities.

In the original Chen model, each attribute is represented using an oval with the attribute name connected to the entity with a line.

The Chen model is especially useful to illustrate some of the conceptual elements of database design.

Attributes do not have a domain.

Attributes cannot share a domain.

In an ER diagram, primary keys are usually bolded.

Ideally, a primary key is composed of several attributes.

A composite key is a primary key composed of more than one attribute.

All attributes are either simple or composite.

All simple attributes are also single-valued.

In the Chen model, a multivalued attribute is connected to the owning entity with a double line.

The DBMS can easily handle multivalued attributes.

Derived attributes are stored in a special database table.

Cardinality expresses the specific number of entity occurrences associated with every occurrence of a related entity.

Cardinality expresses the specific number of entity occurrences associated with one occurrence of the related entity.

In Chen notation, there is no way to represent cardinality.

Connectivities and cardinalities are established by business rules.

All entity relationships can be characterized as weak or strong.

You should always load data from the 1 side of a 1:M relationship.

A weak entity has a primary key that is partially or totally derived from the parent entity in the relationship.

The existence of a mandatory relationship indicates that the minimum cardinality is 1 for the mandatory entity.

Relationship participation is not very important when designing a database.

Database designers must obtain a precise description of the nature of the data and the many uses of such data within an organization.

The ERD is used to graphically represent the ____ database model. a. condensed c. logical b. physical d. conceptual

The Chen model is especially useful to illustrate the database from a(n) ____ perspective. a. developmental c. actual b. conceptual d. specific

Attributes may share a ____. a. name c. location b. domain d. table

The set of possible values for an attribute is a ____. a. domain c. set b. range d. key

In an ER diagram, primary keys are indicated by ____. a. bolding c. underlining b. italics d. a special font

The ideal number of attributes used to make up a primary key is ____. a. zero c. two b. one d. six

The ____ attribute(s) make up the primary key in the table definition: CLASS (CRS_CODE, CLASS_SECTION, CLASS_TIME, CLASS_ROOM, PROF_NUM) a. CRS_CODE b. CLASS_SECTION c. CRS_CODE and CLASS_SECTION d. There is no primary key

A ____ key is a key that consists of more than one attribute. a. primary c. composite b. foreign d. domain

A ____ attribute can be further subdivided to yield additional attributes. a. Composite c. Single-valued b. Simple d. Multivalued

A ____ attribute is one that cannot be subdivided. a. Composite c. Single-valued b. Simple d. Multivalued

A ____ attribute can have only one value. a. Composite c. Single-valued b. Simple d. Multivalued

____ attributes can have several values. a. Composite c. Single-valued b. Simple d. Multivalued

Some attributes are classified as ____. a. simple c. defined b. complex d. grouped

A ____ might be represented with a multivalued attribute. a. Person's name b. Household phone numbers c. Bank account balance d. Book title

The following,____, might be represented with a single-valued attribute. a. Person's phone number(s) b. Car's color c. Employee's educational background d. Person's social security number

The ____ type of attribute cannot be created in a DBMS. a. derived c. simple b. multivalued d. composite

A ____ should be a derived attribute. a. Person's name b. Person's age c. Person's social security number d. Person's phone number

A derived attribute ____. a. must be stored physically within the database b. need not be physically stored within the database c. has many values d. must be based on the value of three or more attributes

A derived attribute is indicated in the Chen model by a ____. a. Single line c. Circle b. Dashed line d. Double line

A relationship is an association between ____. a. objects c. databases b. entities d. fields

Knowing the ____ number of entity occurrences is very helpful at the application software level. a. maximum c. exact b. minimum d. max and min

In the ERD, cardinality is indicated using the ____ notation. a. (max, min) c. [min ... max] b. (min, max) d. {min|max}

Making sure all ____ are identified is a very important part of a database designer's job. a. business rules b. cardinalities c. derived attributes d. relationships

Another word for existence-independent is ____. a. weak c. unary b. alone d. strong

When the PK of one entity does not contain the PK of a related entity, the relationship is ____. a. missing c. strong b. weak d. neutral

If an entity's existence depends on the existence of one or more other entities, it is said to be ____-dependent. a. existence c. business b. relationship d. weak

If an entity can exist apart from one or more related entities, it is said to be ____-independent. a. existence c. business b. relationship d. weak

A ____ entity has a primary key that is partially derived from the parent entity in the relationship. a. strong c. business b. weak d. relationship

The term "____" is used to label any condition in which one or more optional relationships exist. a. participation b. optionality c. cardinality d. connectivity

The existence of a(n) ____ relationship indicates that the minimum cardinality is 1 for the mandatory entity. a. mandatory b. optional c. multivalued d. single-valued

The Crow's foot symbol with two parallel lines indicates ____ cardinality. a. (0,N) c. (1,1) b. (1,N) d. (0,1)

If an employee within an EMPLOYEE entity has a relationship with itself, that relationship is known as a ____ relationship. a. self c. looping b. self-referring d. recursive

A ____ relationship exists when an association is maintained within a single entity. a. unary c. binary b. ternary d. weak

A ____ relationship exists when two entities are associated. a. unary c. ternary b. binary d. weak

A ____ relationship exists when three entities are associated. a. unary c. ternary b. binary d. weak

____ relationships are most common. a. Unary c. Ternary b. Binary d. Higher-degree

A ____ entity is composed of the primary keys of each of the entities to be connected. a. bridge c. unary b. composite d. binary

The bridge entity is known as a ____ entity. a. unary c. strong b. weak d. composite

The step,____, occurs first in the process of building an ERD. a. Develop the initial ERD. b. Create a detailed narrative of the organization's description of operations. c. Identify the attributes and primary keys that adequately describe the entities. d. Identify the business rules based on the description of operations.

Complex ____ requirements may dictate data transformations, and they may expand the number of entities and attributes within the design. a. information c. design b. entity d. processing

The Chen model is specially useful to illustrate some of the ____________________ elements of database design.

The Crow's Foot model is more ____________________-oriented than the Chen model.

The ERM forms the basis of a(n) ____________________.

The ____________________ refers to a specific table row as an entity instance.

____________________ are characteristics of entities.

A(n) ____________________ is the attribute's set of possible values.

____________________ are underlined in an ER diagram.

A person's social security number would be an example of a(n) ____________________ attribute.

____________________ attributes can be subdivided.

A(n) ____________________ attribute cannot be subdivided.

An attribute representing one or more college degrees belonging to a person would be a(n) ____________________ attribute.

Instead of storing a person's age, it is better to store the date of birth and use the difference between that value and the system date as a(n) ____________________ attribute.

A(n) ____________________ attribute need not be physically stored within the database.

Connectivities and cardinalities are usually based on ____________________ rules.

In the relationship "EMPLOYEE claims DEPENDENT" the DEPENDENT entity is ____________________ on the EMPLOYEE entity.

A(n) ____________________ relationship is also known as an identifying relationship.

The Crow's Foot notation depicts the strong relationship with a(n) ____________________ line between the entities.

A weak entity must be ____________________-dependent.

Participation is ____________________ if one entity occurrence does not require a corresponding entity occurrence in a particular relationship.

Relationship strength depends on how the primary key of the related entity is formulated, while the relationship ____________________ depends on how the business rule is written.

In Crow's Foot notation, an optional relationship between entities is shown by drawing a(n) ____________________ on the side of the optional entity.

Failure to understand the distinction between mandatory and optional ____________________ in relationships might yield designs in which awkward (and unnecessary) temporary rows (entity instances) must be created just to accommodate the creation of required entities.

A(n) ____________________ relationship exists when two entities are associated.

In the original ERM described by Chen, relationships do not contain ____________________.

Identifying the attributes of the entities helps you better understand the ____________________ among entities.