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IS230 > Chapter 2 > Flashcards

Chapter 2 Flashcards

1
Q

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.

A

data model

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2
Q

Constructs are used to define the database ______

A

structure

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3
Q

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

A

constructs

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4
Q

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

A

true

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5
Q

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)

A

user-defined

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6
Q

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

A

true

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6
Q

Name 4 Categories of Data Models

A
  • Conceptual (high-level, semantic)
  • Physical (low-level, internal)
  • Implementation (representational)
  • Self-Describing
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7
Q

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

A

conceptual (high-level, semantic)

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8
Q

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

A

conceptual (high-level, semantic)

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9
Q

__________ 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.

A

Physical (low-level, internal)

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10
Q

________ 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)

A

Implementation (representational) data models

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11
Q

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

A

self-descibing

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12
Q

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

A

Database Schema

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13
Q

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

A

Schema Diagram

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14
Q

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

A

Schema Construct

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15
Q

___________ 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.

A

Database State

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16
Q

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

A

Database State

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17
Q

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

A

false, database state not valid state.

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18
Q

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

A

valid state

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19
Q

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

A

Initial Database State

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20
Q

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

A

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

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21
Q

________ is also called intension.

A

Schema

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22
Q

_______ is also called extension.

A

State

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23
Q

___________ 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.)

A

Three-Schema Architecture

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24
Q

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

A

internal, conceptual, external.

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25
Q

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

A

external

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26
Q

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

A

implementation

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27
Q

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

A

internal

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28
Q

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

A

Mappings

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29
Q

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.

A

true.

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30
Q

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

A

logical

31
Q

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

A

false, internal not external.

32
Q

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

A

false, physical not logical

33
Q

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.

A

mappings

34
Q

Name the 2 DBMS Languages.

A
  • Data Definition Language (DDL)
  • Data Manipulation Language (DML)
35
Q

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

A

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

36
Q

What are the two types of DML languages?

A
  • High level or non-procedural
  • low level or procedural
37
Q

___________ Langauge is used to specify database retrievals and updates.

A

Data Manipulation Language (DML)

38
Q

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

A

true

39
Q

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

A

Query Language

40
Q

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

A

Data Definition Language (DDL)

41
Q

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

A

false, DDL not DML.

42
Q

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

A

storage definition language, view definition language.

43
Q

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

A

low-level

44
Q

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

A

low-level

45
Q

(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.

A

high-level

46
Q

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

A

high-level

47
Q

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

A

high-level.

48
Q

Name 3 DBMS Interfaces.

A
  • 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
49
Q

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

A

DBA

50
Q

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

A

Data dictionary / repository

51
Q

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.

A

Active, Passive

52
Q

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

A

Centralized

53
Q

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

A

true

54
Q

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.

A

true

55
Q

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.).

A

true

56
Q

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.

A

true

57
Q

_____________ provides database query and transaction services to the
clients

A

DBMS Server

58
Q

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

A

Relational

59
Q

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

A

true

60
Q

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

A

false, must install appropriate,

61
Q

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

A

the data sources.

61
Q

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

A

web

62
Q

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

A

files, non-DBMS software

63
Q

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

A

application, web

64
Q

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.

A

intermediate layer

65
Q

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

A

intermediate layer

66
Q

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

A

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

67
Q

Name 3 classifications of DBMSs

A
  • 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)
68
Q

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

A

legacy

69
Q

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

A

currently used

70
Q

Name 3 Variations of Distributed DBMSs
(DDBMSs).

A
  • Homogeneous DDBMS
  • Heterogeneous DDBMS
  • Federated or Multidatabase Systems
71
Q

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

A

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

72
Q

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

A

Federated or Multidatabase Systems

73
Q

Name 3 Cost considerations for DBMSs.

A
  • 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.

IS230 (13 decks)

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