CS431- true false questions

A state represents how an object acts

False

An association class is an association that participates in no relationships

False

Distributed databases make data sharing more difficult because of the data communication problems

False

Replicated databases usually result in tightly coupled nodes

False

Replication should NOT be used if timely updates are important

False

applications that can tolerate out-of-date data are not the best candidates for data replication

False

local autonomy means that data are not accessible from remote sites

False

shared ownership of data is most appropriate as business activities move across time zones

False

specifications for transactions do not need to be reviewed quickly

False

Applications such as decision support or data warehousing often do not require current data and are supported by periodic snapshots

True

Horizontal partitioning offers increased efficiency because data are close to use areas

True

Replication is often used for non collaborative data

True

The role of a data warehouse administrator emphasizes integration and coordination of metadata and data across many data sources

True

The role of database administration is typically a more hands-on, physical involvement with the management of databases.

True

a distributed database is NOT just a collection of files

True

a distributed database may require more costly and complez software than a centralized database

True

in a homogeneous environment, the same DBMS is used at each

True

one way to generate messages for near real time replication is through the use of database triggers

True

the data administrator takes responsibility for the overall management of data resources

True

a class diagram shows the dynamic structure of an object-oriented model

false

a class that can have direct instances is called an abstract class

false

a constructor operation does not alter an instance of a class

false

a domain is a way to create a structure that acts like a table

false

a tenary relationship can easily be replaced by three binary relationships

false

an instance of a subclass is not always an instance of its superclass

false

databases are generally the property of a single department within an organization

false

each role has a duplicity which indicates how many objects participate in a given relationship

false

loss of data integrity does not impact the quality of data in a database

false

open-source software always comes with complete documentation

false

users of distributed database systems always need to know the location of the data

false

with an asynchronous distributed database, all data across the network is continuously kept up to date

false

An object encapsulates both data and behavior

true

a class-scope attribute is an attribute of a class that specifies a value common to an instance of a class

true

a class-scope operation applies to a class rather than an object instance

true

a derived attribute, association, or role is one that can be computed or derived from other attributes, associations, or roles

true

a trigger can be used for security purposes to prohibit inappropriate actions, such as changing a salary value outside of a business day

true

a view can be built to present only the data to which a user requires access

true

according to the UML notation guide, the term disjoint means that a descendant many not be descended from more than one of the classes

true

an association class is similar to an associative entity in the E-R model

true

an association role is the end of an association where it connects to a class

true

an object class is a set of objects that share a common structure and behavior

true

an operation is a function or service that is provided by all of the classes

true

authorization rules are controls incorporated in the data management system that restrict access to data and also restrict the actions that people may take when they access the data

true

encapsulation is the technique of hiding the internal implementation details of an object from its external view

true

in a heterogeneous environment, not all users use the same DBMS

true

the goal of database security is the protection of data from accidental or intentional threats to its integrity and access

true

the most common multiplicities are 0..1.,* and 1

true