Database Exam 1
Entity
A real world identifiable object
Entity set
Collection of similar entities
relationship set
Collection of similar relationships
Explain Relation-based tables characteristic of a DBMS
DBMS allows entities and relations around them to form tables
Explain query language of a DBMS as a characteristic of a DBMS
DBMS contains query language which helps get and manipulate data
Explain Multiuser and Concurrent Access as a characteristic of a DBMS
DBMS supports multiusers and allows parallel data access.
While formulating real-world scenario into the database model, the ER Model creates all of the following EXCEPT?
Data
ER model
Defines the conceptual view of the database
One-to-one
Each entity in the relationship will have exactly one related entity
Explain Multiple views as a characteristic of a DBMS
Enables users to have a concentrated view of the database to their specifications
The user(presentation) tier
End-users operate on this tier
Many-to-many
Entities on both sides of the relationship can have many related entities on the other side
Which of the following is NOT true regarding 2-tier architecture?
It is the most widely used architecture to design a DBMS
Designer user type
People the work on designing the database
Attributes
Properties that represent an entity that has values
Explain the Administrators user type
Responsible to look after usage and who should use the dbms
What does NOT define a data model
Stored in a flat file
Explain Security as a characteristic of a DBMS
This enables multiple users to have different views and different features.
End users user type
Those who actually use the database
Entity-Relationship (ER) Model is based on the notion of real-world entities and relationships among them.
True
Multi-value attributes may contain multiple values, such as tow or more phone numbers or email addresses.
True
Single-value attributes contain single value.
True
Tuples are known as records
True
Which of the following is NOT part of the 3-tier Architecture?
View tier
Explain consistency characteristic of a DBMS
Where the relations remain consistent
Explain Isolation of data and application characteristic of a DBMS
a database is an active entity where data is said to be passive.
Describe logical data independence?
a kind of mechanism, which liberalizes itself from actual data changes on table format should not change the data residing on the disk
Entity
a real world object
Which of the following describe a database instance?
a state of operational database with data at any given time contains a snapshot of the database
Which is not a valid mapping cardinality?
all to all
The database (data) tier
at this tier the database resides along with its query processing languages
Simple attribute
atomic values that cannot be further divided
Definition of a dbms
collection interrelated data
Definition of a database
collection of related data
domain
data type
Explain Less redundancy characteristic of a DBMS
dbms follows the rules of normalization
Which of the following describes the Physical Database Schema?
defines how the data will be stored in a secondary storage pertains to the actual storage of data and its form of storage like files, indices, etc
Which of the following describes the Logical Database Schema?
defines tables, views, and integrity constraints defines all the logical constraints that need to be applied on the data stored
mapping cardinalities
defines the number of assoication between two entities
Which of the following describe a database schema?
is the skeleton structure that represents the logical view of the entire database defines its entities and the relationship among them defines how the data is organized
Which of the following is NOT true regarding 1-tier architecture?
it must have an application through which the DBMS can be accessed
Describe logical data
it stores information about how data is managed inside data about database
relationship
logical association among entities
Candidate key
minimal super key
Real-world entity characteristic
modern dbms are realistic and uses real-world entities to design its architecture
Degree of relationship
number of participating entities in a relationship
Primary Key
one of the candidate keys
attribute
property or characteristic
Definition of data
represents recordable facts
Super key
set of attribute that identifies an entity
The application(middle) tier
the application server and the programs that access the database reside on this tier
Attributes are known as columns
true
tables are known as relations
true
One-to-many
An entity on one side of the relationship can have many related entities, but an entity on the other side will have a maximum of one related entity
relationship
Association between entities
Explain ACID properties as a characteristic of a DBMS
Atomicity, Consistency, Isolation, Durability.
Composite attributes
Attributes that consist of multiple simple attributes
Derived attributes
Attributes that do not exist in the database but their values are derived from other attributes