Chapter 2

Question 1

a set of concepts to describe the structure of a database, the operations for manipulating these structures, and certain constraints that the database should obey.

Answer 1

data model

Question 2

Constructs are used to define the database ______

Answer 2

structure

Question 3

_________ typically include elements (and their data
types) as well as groups of elements (e.g. entity, record,
table), and relationships among such groups.

Answer 3

constructs

Question 4

T/F: Constraints specify some restrictions on valid data; these
constraints must be enforced at all times.

Answer 4

true

Question 5

Operations on the data model may include basic
model operations (e.g. generic insert, delete,
update) and __________ operations (e.g.
compute_student_gpa, update_inventory)

Answer 5

user-defined

Question 6

T/F: Data model operations are used for specifying database retrievals and updates by referring to the
constructs of the data model.

Answer 6

true

Question 6

Name 4 Categories of Data Models

Answer 6

• Conceptual (high-level, semantic)
• Physical (low-level, internal)
• Implementation (representational)
• Self-Describing

Question 7

_____________ data models are also called entity-based or object-based data models.

Answer 7

conceptual (high-level, semantic)

Question 8

___________ data models provide concepts that are close to the way many users perceive
data.

Answer 8

conceptual (high-level, semantic)

Question 9

__________ data models provide concepts that describe details of how data is stored in the computer. are usually specified in an ad-hoc manner through DBMS design and administration manuals.

Answer 9

Physical (low-level, internal)

Question 10

________ data models provide concepts that fall between the high-level and low-level data models, used by many commercial DBMS implementations (e.g. relational data models
used in many commercial systems)

Answer 10

Implementation (representational) data models

Question 11

___________ data models combine the description of data with the data values. Examples
include XML, key-value stores and some NOSQL systems

Answer 11

self-descibing

Question 12

___________ is the description of a database. It includes descriptions of the database structure, data types, and the constraints on the database.

Answer 12

Database Schema

Question 13

_________ is an illustrative display of (most aspects of) a database schema.

Answer 13

Schema Diagram

Question 14

_____________ is a component of the schema or an object within the schema, e.g., STUDENT, COURSE.

Answer 14

Schema Construct

Question 15

___________ is the actual data stored in a database at a particular moment in time. This includes the
collection of all the data in the database.

Answer 15

Database State

Question 16

________ is also called database instance (or occurrence or snapshot).

Answer 16

Database State

Question 17

T/F: Valid state refers to the content of a database at a moment in time.

Answer 17

false, database state not valid state.

Question 18

___________ is a state that satisfies the structure and constraints of the database.

Answer 18

valid state

Question 19

__________ refers to the database state when it is initially loaded into the system.

Answer 19

Initial Database State

Question 20

T/F: The database schema changes every time the
database is updated.

Answer 20

false, database state not the database schema.
the database schema changes VERY INFREQUENTLY.

Question 21

________ is also called intension.

Answer 21

Schema

Question 22

_______ is also called extension.

Answer 22

State

Question 23

___________ is proposed to support DBMS characteristics of Program-data independence, Support of multiple views of the data, and self-describing nature of DB system. (Not explicitly used in commercial DBMS products,
but has been useful in explaining database
system organization.)

Answer 23

Three-Schema Architecture

Question 24

Three-Schema Architecture defines DBMS schemas at three levels: ________ schemas, _________ schemas , and ________ schemas.

Answer 24

internal, conceptual, external.

Question 25

________ schemas are at the external level to describe the various user views. It usually uses the same data model as the conceptual schema.

Answer 25

external

Question 26

The conceptual schema uses a conceptual or an __________ data model.

Answer 26

implementation

Question 27

__________ schemas are at the internal level to describe physical storage structures and access paths (e.g indexes). It typically uses a physical data model.

Answer 27

internal

Question 28

__________ among schema levels are needed to transform requests and data.

Answer 28

Mappings

Question 29

T/F: In mappings among schema levels, programs refer to an external schema, and are mapped by the DBMS to the internal schema for execution.

Answer 29

true.

Question 30

(Logical/Physical) data independence isthe capacity to change the conceptual schema without having to change the external schemas and their associated application programs.

Answer 30

logical

Question 31

T/F: Physical data independence is the capacity to change the external schema without having to change the conceptual schema.

Answer 31

false, internal not external.

Question 32

T/F: Generally, logical data independence exists in most databases and file environments.

Answer 32

false, physical not logical

Question 33

When a schema at a lower level is changed, only the ________ between this schema and higherlevel schemas need to be changed in a DBMS that fully supports data independence. The higher-level schemas themselves are unchanged. Hence, the application programs need not be changed since they refer to the external schemas.

Answer 33

mappings

Question 34

Name the 2 DBMS Languages.

Answer 34

- Data Definition Language (DDL) - Data Manipulation Language (DML)

Question 35

T/F: High Level or Non-procedural languages must be embedded in a programming language while Low Level or Procedural Languages do not.

Answer 35

false, low level or procedural languages *must be* embedding in a programming language while high level or non-procedural language can be used in a standalone way or MAY be embedded in a programming language

Question 36

What are the two types of DML languages?

Answer 36

- High level or non-procedural - low level or procedural

Question 37

___________ Langauge is used to specify database retrievals and updates.

Answer 37

Data Manipulation Language (DML)

Question 38

T/F: DML commands (data sublanguage) can be embedded in a general-purpose programming language (host language).

Answer 38

true

Question 39

_____________ are stand-alone DML commands that can be applied directly.

Answer 39

Query Language

Question 40

___________ Language is used by the DBA and database designers to specify the conceptual schema of a database.

Answer 40

Data Definition Language (DDL)

Question 41

T/F: In many DBMSs, the DML is also used to define internal and external schemas (views).

Answer 41

false, DDL not DML.

Question 42

In some DBMSs, separate __________ (SDL) and ____________(VDL) are used to define internal and external schemas.

Answer 42

storage definition language, view definition language.

Question 43

In (Low-level/High-level) DML langauge, Constructs such as looping are needed to retrieve multiple records, along with positioning pointers.

Answer 43

low-level

Question 44

(Low-level/High-level) DML langauge retrieves data one “record”-oriented (record-at-a-time).

Answer 44

low-level

Question 45

(Low-level/High-level) DML langauge are “set”-oriented (set-at-a-time) and specify what data to retrieve rather than how to retrieve it.

Answer 45

high-level

Question 46

(Low-level/High-level) DML langauge are also called declarative languages.

Answer 46

high-level

Question 47

The SQL relational language is an example of (Low-level/High-level) DML langauge.

Answer 47

high-level.

Question 48

Name 3 DBMS Interfaces.

Answer 48

- Stand-alone query language interfaces - Programmer interfaces for embedding DML in programming languages - User-friendly interfaces (Menu-based, forms-based, graphics-based, mobile-interfaces, natural language [requests in written english]) - Speech : Input query and Output response - Web Browser with keyword search

Question 49

Creating user accounts, granting authorizations, Setting system parameters, Changing schemas or access paths are interfaces for the __________.

Answer 49

DBA

Question 50

__________ are used to store schema descriptions and other information such as design decisions, application program descriptions, user information, usage standards, etc.

Answer 50

Data dictionary / repository

Question 51

There are two kinds of data dictionaries: _______ data dictionary is accessed by DBMS software and users/DBA, while the ___________ data dictionary is accessed by users/DBA only.

Answer 51

Active, Passive

Question 52

____________ DBMS Combines everything into single system including DBMS software, hardware, application programs, and user interface processing software.

Answer 52

Centralized

Question 53

T/F: In a centralized DBMS architecture a user can still connect through a remote terminal. however, all processing is done at centralized site.

Answer 53

true

Question 54

T/F: In Basic 2-tier Client-Server Architectures, clients can accesss the specialized servers with specialized functions (ex: print server, file server, email server, etc) as needed.

Answer 54

true

Question 55

T/F: In 2-tier client-server architectures, Clients may be diskless machines or PCs or Workstations with disks with only the client software installed, and are connected to the servers via some form of a network (LAN: local area network, wireless network, etc.).

Answer 55

true

Question 56

T/F: In 2-tier client-server architectures, appropriate interfaces are provided through a client software module to access and utilize the various server resources.

Answer 56

true

Question 57

_____________ provides database query and transaction services to the clients

Answer 57

DBMS Server

Question 58

_________ DBMS servers are often called SQL servers, query servers, or transaction servers

Answer 58

Relational

Question 59

T/F: Applications running on clients utilize an Application Program Interface (API) to access server databases via standard interface such as: ODBC or JDBC.

Answer 59

true

Question 60

T/F: Client and server must install any client module and server module software for ODBC or JDBC.

Answer 60

false, must install appropriate,

Question 61

A client program may connect to several DBMSs, sometimes called __________.

Answer 61

the data sources.

Question 61

Three Tier Client-Server Architecture are common for _________ applications.

Answer 61

web

Question 62

In general, data sources can be ______ or other ____________ that manages data

Answer 62

files, non-DBMS software

Question 63

In the Three Tier Client-Server Architecture, the intermediate layer called ________ or ________ server.

Answer 63

application, web

Question 64

The ______________ in the Three Tier Client-Server Architecture, stores the web connectivity software and the business logic part of the application used to access the corresponding data from the database server.

Answer 64

intermediate layer

Question 65

The ___________ in the Three Tier Client-Server Architecture acts like a conduit for sending partially processed data between the database server and the client.

Answer 65

intermediate layer

Question 66

T/F: Three-tier Architecture Can Enhance Security.

Answer 66

True, because the database server only accessible via middle tier as in cannot directly access the database server.

Question 67

Name 3 classifications of DBMSs

Answer 67

- Based on the data model used - Single-user (typically used with personal computers) vs. multi-user (most DBMSs). - Centralized (uses a single computer with one database) vs. distributed (multiple computers, multiple DBs)

Question 68

Network and Hierarchical are ________ data model based classifications of DBMSs.

Answer 68

legacy

Question 69

Relational, Object-oriented, Object-relational are ________ data model based classifications of DBMSs.

Answer 69

currently used

Question 70

Name 3 Variations of Distributed DBMSs (DDBMSs).

Answer 70

- Homogeneous DDBMS - Heterogeneous DDBMS - Federated or Multidatabase Systems

Question 71

T/F: Distributed Database Systems have now come to be known as client-server based database systems.

Answer 71

true, because They do not support a totally distributed environment, but rather a set of database servers supporting a set of clients

Question 72

In (homogeneous/Federated or Multidatabase Systems), Participating Databases are loosely coupled with high degree of autonomy.

Answer 72

Federated or Multidatabase Systems

Question 73

Name 3 Cost considerations for DBMSs.

Answer 73

- Cost Range: from free open-source systems to configurations costing millions of dollars. - Different licensing options: site license, maximum number of concurrent users (seat license), single user, etc. - Commercial DBMS offer additional specialized modules. - Type of access paths within database system. - General Purpose vs. Special Purpose.