Database Systems Quiz #1 & #2
entities
Customers, cars, and parts are exampled of:
Recursive relationships
Relationships among entities of the same type are called ___?
Database Instance
Snapshot of the data in the database at a given instant of time is called
disjoint
The ___ rule specifies that an entity can be a member of only one subtype at a time.
partial specialization
The ___ rule specifies that an entity isntance of a supertype is allowed not to belong to any subtype.
snapshot
The a ___ of course data gies the values of all attributes, such as title and department, of all courses at a particular point in time.
DBMS system designers and implementors
They design and implement the DBMS modeuls and interfaces as a software package
Application Programs
To allow users to manipulate the information, the syste has a number of
Primary key values cannot be null according to the entity integrity constraint.
What is TRUE about Entity Integrity Constraints?
Instance
What term is used to refer to a specific record in your music database; for isntance; information stored about a specific album
Phone_number
Which of the following can be a multivalues attribute?
All of the above (DDL, DML, DQL)
Which of the following is Database Language?
total specialization
Which of the following is a completeness constraint?
Suptertype
Which of the following is a generic entity type that has a relationship with one or more subtypes
Network Model
Which of the following is a navigation data model model
Network Maintenance
Which of the following is not a functions of DBA?
Critical Level
Which of the following is not a level of data abstraction
HTML
Which of the following is not involved in DBMS
user
Which of the following isn't a level of abstraction
Enroll
Which would most likely NOT be an entity on an ERM
FALSE
With the traditional file processing approach, each application shares data files, thus enabling much data sharing
Database designers
___ are considered database architects
alter
___ command can be used to modify a column in a table
an attribute or set of attributes that can be the primary key
a "candidate key" is:
All of the above (Collection of data describing one particular enterprise, Collection of programs to access data, Collection of interrelated data)
A Database System is:
disjoint rule
A ___ addresses whether an instance of a supertype may simultaneously be a member of two or more subtypes.
data warehouse
A ___ focuses primarily on storing data used to generate information required to make tactical or strategic decisions
schema
A ___ is used to define overall design of the database
Attribute
A characteristic of an entity
TRUE
A data model is a graphical system used to capture the nature and relationships among data
indivisible
A domain is atomic if elements of the domain are considered to be ___ units.
physical
A level that described how a record is stored
logical
A level that describes data stored in a database and the relationships among the data
Schema
A logical structure of the database
none of the above (does not depend on anything)
A strong entity depends on the following:
Data model
A type of data abstraction that is used to provide a conceptual representation
completeness
A(n) ___ constraint is a type of constraint that addresses whether an insance of a supertype must also be an instance of atleast one subtype.
conceptual
A(n) ___ model is independent of both hardware and software
b and c (Belong to the same entity class & Have the same attributes)
All isntances of a given entity?
derived attribute
An attribute of an entity that is computed is a(n):
One-to-one
An entity in A is associated with at most one entity in B, and an entity in B is associated with at most one entity in A. This is called as
weak
An entity type whose existance depends on another entity type is called a ___ entity
Geographic Information systems (GIS)
Can store and analyze maps, weather data, and satellite images
Both A and B (Data independence & centralized control of data)
DBMS helps achieve
Programs
DBMS is a set of ___ to access the data
End Users
DBMS manages the interaction between ___ and database.
Create information table in the Database
Data Manipulation Language (DML) is not to
All the above (Retrieval of information stored in database, Insertion of new information into the database, Deletion of information from the database)
Data Manipulation Language enables users to
redundancy
Data ___ exists when the dame data are stored unnecessarily at different places
Both B & C (Programs are not dependent on the physical attributes of data & Programs are not dependent on th elogical attributes of data)
Data independence means
File processing system
Data redundancy and Data inconsistency is one of the major drawbacks of
Call the DBMS to access stored data
Database processing programs
cascade
Deletion of an employee from table also delete that employee from another table. This kind of delete is called ___
assertion
Domain constraints, functional dependency and referencetial integrity are special forms of ___.
FALSE
ERM is an acronym for Enterprise Reliability Model
All of the above (Data is separated and isolated, Data is often duplciated, Application programs are dependent on file format)
File processing systems have important limitations
only one supertype
In a supertype/subtype hierarchy, each subtype has:
supertypes
In a supertype/subtype hierarchy, subtypes that are lower in the hierarchy inherit attributes from not only their immediate supertype but from all ___ in the hierarchy.
FALSE
In an entity called STUDENT, you might find attributes of PROFESSOR-ID, Last-Name, First-Name, and CLASSROOM
A multivalues attribute of an entity set
In which of the following, a separate relation is created consisting of that attribute and the primary key of the entity set.
Stringent real-time requirements
It is better to use fiels than a DBMS when there are
Delete from R2
Let R1(A, B, C, D) and R2(P, Q, R, S) be two relations in which A is the foreign key of R1 that refers to the primary key of R2. Which of the following operations causes the referential integrity constraint violation
Database Schema
Logical design of database is called
Both the statems are true
Statement 1: A tuple is a row in a relation. Statement 2: Existance of multiple foreign keys in a same relation is possible.
there are attributes that apply to some but not all instances of an entity type
Subtypes should be used when:
any
The Tuples of the relations can be of ___ order.
view
The ___ level helps applciation programs hide the details of data types
total specialization
The ___ rule specified that each entity isntance of the supertype must be a member of some subtype in the relationship.
tree structure
The hierarchical database model is based on a
predicate-defined subclass
The kind of subclass on which the entity become part of subclass by putting some condition on attribute value sis classified as
entity-relationship model
The logical representation of an organization's data is called a(n):
one
The number of entity types that participate in a Unary relationship is:
specialization
The process of defining one or more subtypes of a supertype and forming relationships is called:
All of the above (It is an integrated collection of logically related records, It consolidated separate files into a common pool of data records, Data stored in a database is independent of the application programs using it)
The property / properties of a database is / are:
Constraint
The restrictions placed on the data
subset of the union of all its superclasses
The set of entities in a union (category) class is
No proper subset is also a super key
The subset of a super key is a candidate key under what condition?
No proper subset is a super key
The subset of super key is a candidate key under what condition?
Relationship, attribute, entity
The three major parts of an ERM diagram are:
Instance
he actual content in the database at a particular point