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applications that can tolerate out-of-date data are not the best candidates for data replication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