Modern Database Management - Self Check 04

A(n) ________ is a set of values that may be assigned to an attribute

domain

An anomaly is a type of flaw in the database server

f

An enterprise key is a foreign key whose value is unique across all relations

f

An identifier assigned to an associative entity is also called a cross-relation key

fa

Anomalies do not generally arise out of transitive dependencies

fa

CASE tools can model more complex data relationships, such as ternary relationships

fa

Data integrity consists of powerful operations to manipulate data stored in relations

fal

A foreign key is a primary key of a relation that also is a primary key in another relation

false

A relation is in first normal form if it has no more than one multivalued 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

In the relational data model, associations between tables are defined through the use of primary keys

false

The relational data model does at this time directly support subtype/supertype relationships.

false

The truncate table statement in SQL creates a new table

false

There can be multivalued attributes in a relation.

false

Unlike columns, the rows of a relation may not be interchanged and must be stored in one sequence

false

View integration is the process of merging relations together

false

When transforming a one-to-one relationship, a new relation is always created.

false

When transforming a unary many-to-many relationship to relations, a recursive foreign key is used

false

When transforming a weak entity, one should create one relation with both the attributes of the strong entity and the attributes of the weak entity.

false

A relation that contains no multivalued attributes is in ________ normal form.

first

The entity integrity rule states that a primary key attribute can be null

flase

An attribute in a relation that serves as the primary key of another relation in the same database is called a(n)_____

foreign key

A referential integrity constraint states that each ________ value must match a(n) ________ value in another relation or be blank

foreign key primary key

A(n) ________ is a constraint between two attributes or two sets of attributes

functional dependancy

Associative entities are also called ______

gerunds

An attribute that may have more than one meaning is called a(n)_____

homonym

The first step in transforming EER diagrams into relations is to ________.

map regular entities

The process of decomposing relations with anomalies to create smaller, well-structured relations is called ________.

normalization

When creating tables using the CREATE TABLE statement, NOT NULL constrains an attribute from being assigned a(n) ________ value

null

A ________ is a functional dependency where one or more nonkey attributes are functionally dependent on part (but not all) of the primary key

partial functional dependancy

A weak entity must always have a(n) ________ that distinguishes the various occurrences of the weak entity for each owner entity instance

partial identifier

A(n) ________ is an attribute that uniquely identifies each row in a relation

primary key

A(n) ________ is one that references the primary key values of the same relation

recursive foreign key

A(n) ________ is a rule that states that either each foreign key value must match a primary key value in another relation or the foreign key value must be null

referential integrity constraint

The ________ states that no primary key attribute can be null

referential integrity constraint

A named, two-dimensional table of data is called a(n)

relation

Sometimes, associative entities have ________ identifiers assigned to them

surrogate

A cascading delete removes all records in other tables associated with the record to be deleted

tRUE

A ________ dependency is a functional dependency between the primary key and one or more nonkey attributes that are dependent upon the primary key via another nonkey attribute.

transitive

A candidate key is an attribute, or combination of attributes, that uniquely identifies a row in a relation.

true

A partial functional dependency is a functional dependency in which one or more non-key attributes are functionally dependent on part (but not all) of the primary key.

true

A primary key is an attribute that uniquely identifies each row in a relation

true

A relation in fifth normal form may not contain any anomalies

true

A well-structured relation contains minimal redundancy and allows users to manipulate the relation without errors or inconsistencies

true

All values that appear in a column of a relation must be taken from the same domain

true

Data structures include data organized in the form of tables with rows and columns

true

If an identifier is not assigned, the default primary key for an associative relation consists of the two primary key attributes from the other two relations

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

The columns of a relation can be interchanged without changing the meaning or use of the relation

true

When a regular entity type contains a multivalued attribute, two relations are created

true

When normalizing, the goal is to decompose relations with anomalies to produce smaller, well-structured relations

true

When two or more attributes describe the same characteristic of an entity, they are synonyms

true

An attribute or combination of attributes that uniquely identifies a row in a relation is called a(n)_______

candidate key

A primary key that consists of two or more attributes is called a(n) ________ key

composite

An error or inconsistency resulting from redundancy in tables is called a(n)______

anomaly

A composite key consists of only one attribute

F

A co-dependency is a constraint between two attributes or two sets of attributes

False

The primary key of the many side migrates to the one side when transforming a one-to-many relationship

False

A referential integrity constraint is a rule that maintains consistency among the rows of two relations

True

An alternative name for an attribute is a(n)

alias