Data Modeling Foundations

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Mid-Term Review Chapters 1 - 5

Information

____ is used to reveal the meaning of data.

Good decision making

Accurate, relevant, and timely information is the key to ___.

row facts of interest to the end-user

End-user data is _____.

Metadata

____ provides a description of the data characteristics and the set of relationships that link the data found within the database.

DBMS

The ____ serves as the intermediary between the user and the database.

application program

A(n) ____ might be written by a programmer or it might be created through a DBMS utility program.

query result set

The response of the DBMS to a query is the ____.

enterprise

A(n) ____ database is designed to support a company's day-to-day operations.

workgroup

A(n) ___ database is used by an organization and supports many users across many departments.

multiuser

A workgroup database is a(n) ___ database.

operational databases

Most decision-support data are based on historical data obtained from ___.

unstructured

____ data exist in the format in which they were collected.

unstructured

____ data exist in a format that does not lend itself to processing that yields information.

structured

____ data are the result of formatting to facilitate storage, use and generation of information.

semistructured

Most data you encounter is best classified as ____.

spreadsheet

Which of the following is an example of structured data?

semistructured

XML data is ____.

record

A ___ is a logically connected set of one or more fields that describes a person, place or thing.

file

A ____ is a collection of related records.

model

A(n) ______'s main function is to help you understand the complexities of the real-world environment.

entity

A(n) ___ represents a particular type of object in the real world.

entity

A(n) ___ is anything about which data are to be collected and stored.

attribute

A(n) ___ is equivalent of a field file system.

relationship

A(n) ___ is bidirectional.

constraint

A(n) ____ is a restriction placed on the data.

constraints

___ are important because they help to ensure data integrity.

constraints

___ are normally expressed in the form of rules.

many to many

Students and classes have a ___ relationship.

a detailed description of organization operations

business rules are derived from ___.

serve as a communication tool between the users and designers

Which of the following is true of business rules?

entity

A noun in a business rule translates to a(n) ___ in the data model.

relationship

A verb associating two nouns in a business rule translates to a(n) ___ in the data model.

1960's

The hierarchical data model was developed in the ____.

1980's

The object oriented data model was developed in the ____.

file system data model

VMS/VSAM is an example of a(n) _____.

XML/Hybrid data model

Oracle 11g is an example of a(n) _____.

relational data model

MySQL is an example of
a(n) _____.

hierarchical

In the ___ model, the basic logical structure is represented as an upside-down tree.

hierarchical

In the ___ model, each parent can have many children, but each child has only one parent.

1970's

The relational data model was developed in the ____.

network

In the ___ model, the user perceives the database as a collection of records in 1:M relationships, where each record can have more than one parent.

(DDL) data definition language

A(n) _____ enables a database administrator to define schema components.

entity relationship

The ____ model was developed to allow designers to use a graphical tool to examine structures rather than describing them with text.

entity relationship

The ___ model uses the term connectivity to label the relationship types.

object-oriented

The ___ data model is said to be a semantic data model.

object-oriented

The ___ data model uses the concept of inheritance.

hierarchical

One of the limitations of the ____ model is that there is a lack of standards.

external

The ___ model is the end users' view of the data environment.

conceptual

A(n) ____ model represents a global view of the database as viewed by the entire organization.

logically, physically

The relational database model enables you to view data ___ rather than ____.

table

A(n) ____ is perceived as a two-dimensional structure composed of rows and columns.

Julian

Date Attributes contain calendar dates stored in a special format known as the ___ date format.

determines

In the context of a database table, the statement "A___B" indicates that if you know the value of attribute A, you can look up the value of attribute B.

functionally dependent on

The attribute B is ___ the attribute A if each value in column A determines one and only one value in column B.

superkey

A ___ is any key that uniquely identifies each row.

null

No data entry at all is known as a ___.

redundancy

Controlled ___ makes a relational database work.

secondary

A ___ key is defined as a key that is used strictly for data retrieval purposes.

candidate

A ___ key can be described as a superkey without unnecessary attributes, that is, a minimal superkey.

not null

The ___ constraint can be placed on a column to ensure that every row in the table has a value for that column.

select

To be considered minimally relational, the DBMS must support the key relational operators ____, PROJECT and JOIN.

select

____, also known as RESTRICT, yields values for all rows found in a table that satisfy a given condition.

project

____ yields a vertical subset of a table.

union

___ combines all rows from two tables, excluding duplicate rows.

intersect

____ yields only the rows that appear in both tables.

natural

A(n) ____ join links tables by selecting only the rows with common values in their common attribute(s).

=

The equijoin takes its name from the comparison operator ___used in the condition.

inner

A(n) ____ join only returns matched records from the tables that are being joined.

data dictionary

A ___ contains at least all of the attribute names and characteristics for each table in the system.

system catalog

The ___ is actually a system-created database whose tables store the user/designer-created database characteristics and contents.

synonym

In a database context, a(n) ___ indicates the use of different names to describe the same attribute.

1:M

The ___relational type is the "relational model ideal."

1:1

The ___ relationship should be rare in any relation database design.

bridge

Another name for a composite entity is a ___ entity.

index

A(n) ____ is an ordered arrangement of keys and pointers.

unique

When you define a table's primary key, the DBMS automatically creates a(n) ___ index on the primary key
column(s) you declared.

logical data independence

Codd's Rule of ___ states: Application programs & ad hoc facilities are logically unaffected when changes are made to the table structures that preserve the original table values (changing order of columns or inserting columns.)

nonsubversion

Codd's Rule of ___ states: If the system supports low-level access to the data, users must not be allowed to bypass the integrity rules of the database.

conceptual

The ERD represents the ___ database as viewed by the end user.

conceptual

Some ___ database modeling concepts can be expressed only using the Chen notation.

domain

Attributes may share a ____.

domain

The set of possible values for an attribute is a ___.

underlining

In an ER diagram, primary keys are indicated by ___.

one

Ideally, an entity identifier is composed of ___ attributes.

composite

A ___ identifier is composed of more than one attribute.

composite

A ___ attribute can be further subdivided to yield additional attributes.

simple

A ___ attribute is one that cannot be subdivided.

singlevalued

A ____ attribute can have only one value.

multivalued

____ attributes can have many values.

simple

Some attributes are classified as _____.

M:N

Although the conceptual model can handle ____ relationships and multivalued attributes, you should not implement them in the RDBMS.

person's age

A ___ should be a derived attribute.

need not be stored physically

A derived attribute ____.

dashed line

A derived attribute is indicated in the Chen model by a ____.

entities

A relationship is an association between ____.

maximum & minimum

Knowing the ___ number of entity occurrences is very helpful at the application software level.

(min, max)

In the ERD, cardinality is indicated using the ____ notation.

strong

Another word for existence-independent is ____.

existence

An entity is said to be ___-dependent if it can exist in the database only when it is associated with another related

existence

If an entity can exist apart from one or more related entities, it is said to be ____-independent.

weak

When the PK of one entity does not contain the PK of a related entity, the relationship is ____.

weak

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

optionality

The term ____ is used to label any condition in which one or more optional relationships exist.

mandatory

The existence of a(n) ____ relationship indicates that the minimum cardinality is at least 1 for the mandatory entity.

(1, 1)

The Crow's foot symbol with two parallel lines indicates ____ cardinality.

Binary

A ___ relationship exists when two entities are associated.

Unary

A ___ relationship exists when an association is maintained within a single entity.

Ternary

A ___ relationship exists when three entities are associated.

Binary

____ relationships are most common.

recursive

If an employee within an EMPLOYEE entity has a relationship with itself, that relationship is known as a ___ relationship.

associative

A(n) ____ entity is composed of the primary keys of each of the entities to be connected.

composite

The associative entity is also known as a ___ entity.

detailed narrative of the organizations description of operations

The following step occurs first in the process of building an ERD: ____.

optional

If Tiny College had some departments that were classified as "research only," they would not offer courses; therefore, the COURSE entity would be ___ to the DEPARTMENT entity.

weak

The M:N relationship between STUDENT and CLASS must be divided into two 1:M relationships through the use of the ENROLL entity; the ENROLL entity is ____.

derived

If the focus is on data-retrieval speed, you might also be forced to include ___ attributes in the design, which would not ordinarily be done.

information

Complex ___ requirements may dictate data transformations, and they may expand the number of entities and attributes within the design.

enhanced entity relationship model

The extended entity relationship model (EERM) is sometimes referred to as the ___.

An entity supertype

____ is a generic entity type that is related to one or more entity subtypes.

specialization hierarchy

The ___ depicts the arrangement of higher-level entity supertypes (patient entities) and lower-level entity subtypes.

only one

Within a specialization hierarchy, every subtype can have ___ supertype to which it is directly related.

many

A specialization hierarchy can have ___ levels of supertype relationships.

inheritance

The property of ___ enables an entity subtype to inherit the attributes and relationships of the the supertype.

primary

One important inheritance characteristic is that all entity subtypes inherit their ___ key attribute from their supertype.

1:1

at the implementation level, the supertype and its subtypes depicted in the specialization hierarchy maintain a ___ relationship.

subtype discriminator

A ___ is the attribute in the supertype entity that determines to which entity subtype each supertype occurrence is related.

equality

The default comparison condition for the subtype discriminator attribute is the ___ comparison.

unique

non-overlapping subtypes are subtypes that contain a ___ subset of the supertype entity set.

nonunique

Overlapping subtypes are subtypes that contain ___ subsets of the supertype entity set.

circle over a single line

Partial completeness is symbolized by ___.

generalization

is the bottom-up process of identifying a highter-level, more generic entity supertype from lower-level entity subtypes.

A single abstract entity object

An entity cluster is formed by combining multiple interrelated entities into ___.

primary

the most important characteristic of an entity is its ___ key, used to uniquely identify each entity instance.

natural

A ___ key is a real-world, generally accepted identifier used to uniquely identify real-world objects.

natural identifier

If one exists, a data modeler used a ___ as the primary key of the entity being modeled.

entity instance or row

The primary key's main function is to uniquely identify a ___ within a table.

M:N

Composite primary keys are particularly useful as identifiers of composite entities, where each primary key combination is allowed only once in the ____ relationship.

Unique values

The "____" characteristic of a primary key states the following: The PK must uniquely identify each entity instance. A primary key must be able to guarantee unique values.

security-compliant

The "____" characteristic of a primary key states the following: The selected primary key must not be composed of any attributes that might be considered a security risk or violation.

nonintelligent

The "____" characteristic of a primary key states the following: The PK should not have embedded semantic meaning. An attribute with embedded semantic meaning is probably better used as a descriptive characteristic of the entity rather than as an identifier.

natural

Surrogate primary keys are especially helpful when there is no ___ key.

Foreign

___ keys work with primary keys to properly implement relationships in the relational model.

place a foreign key in one of the entities

The preferred placement for a foreign key when working with a 1:1 relationship is to ___.

one side is mandatory and the other side is optional

When selecting a foreign key placement for a 1:1 relationship, place the PK of the entity on the mandatory side in the entity on the optional side as a FK, and make the FK mandatory when ___.

Time-variant

___ data refer to data whose values change over time and for which you must keep a history of the data changes.

fan trap

a __ occurs when you have one entity in tow 1:M relationships to other entities , thus producing an association among the other entities that is not expressed in that model.

Redundant

___ relationships occur when there are multiple relationship paths between related entities.

formatted

Raw data must be properly ____ formatted for storage, processing and presentation.

management

Data ___ is a discipline that focuses on proper generation, storage and retrieval of data.

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