Chap 2 (Database System Concepts and Architecture)

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

are used to define the database structure

Answer 2

Constructs

Question 3

Constructs typically include

Answer 3

elements (and their data types)
groups of elements (e.g. entity, record, table)
relationships among such groups

Question 4

specify some restrictions on valid data; these constraints must be enforced at all times

Answer 4

Constraints

Question 5

These operations are used for specifying database retrievals and updates by referring to the constructs of the data model.

Answer 5

Data Model Operations

Question 6

Operations on the data model may include

Answer 6

basic model operations (e.g. generic insert, delete, update)
user-defined operations (e.g. compute_student_gpa, update_inventory)

Question 7

Provide concepts that are close to the way many users perceive data.

Answer 7

Conceptual (high-level, semantic) data models

Question 8

Conceptual (high-level, semantic) data models are also called

Answer 8

entity-based or object-based data models

Question 9

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

Answer 9

Physical (low-level, internal) data models

Question 10

Provide concepts that fall between conceptual and physical 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

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

Answer 11

Self-Describing Data Models

Question 12

The description of a database.

Answer 12

Database Schema

Question 13

Database schema includes

Answer 13

descriptions of the database structure, data types, and the constraints on the database.

Question 14

An illustrative display of (most aspects of) a database schema.

Answer 14

Schema Diagram

Question 15

A component of the schema or an object within the schema, e.g., STUDENT, COURSE.

Answer 15

Schema Construct

Question 16

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 16

Database State

Question 17

Database State also called

Answer 17

Database Instance (or Occurrence/Snapshot)

Question 18

The term _____ is also applied to individual database components in database state

Answer 18

instance (e.g record instance, table instance, etc)

Question 19

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

Answer 19

Initial Database State

Question 20

A state that satisfies the structure and constraints of the database.

Answer 20

Valid State

Question 21

The _______ changes very infrequently

Answer 21

database schema

Question 22

The ______ changes every time the database is updated.

Answer 22

database state

Question 23

Schema is also called

Answer 23

Intension

Question 24

State is also called

Answer 24

extension

Question 25

Three-Schema Architecture was proposed to support DBMS characteristics of

Answer 25

Program-data interdependence Support multiple views of data

Question 26

Three-Schema Architecture defines DBMS Schemas at three levels which are

Answer 26

Internal schema Conceptual schema External schema

Question 27

at the internal level to describe physical storage structures and access paths (e.g indexes).

Answer 27

Internal Schema

Question 28

at the conceptual level to describe the structure and constraints for the whole database for a community of users.

Answer 28

Conceptual Schema

Question 29

at the external level to describe the various user views.

Answer 29

External schema

Question 30

What does internals schema typically use

Answer 30

Physical data model

Question 31

Conceptual schema uses what model

Answer 31

conceptual or implementation data model

Question 32

External schema uses what model

Answer 32

conceptual or implementation data model

Question 33

In Three-Schema Architecture, _____ among schema levels are needed to transform requests and data

Answer 33

mappings

Question 34

The capacity to change the conceptual schema without having to change the external schemas and their associated application programs

Answer 34

Logical Data Independence

Question 35

The capacity to change the internal schema without having to change the conceptual schema

Answer 35

Physical Data Independence

Question 36

When a schema at a lower level is changed, only the _____ between this schema and higher-level schemas need to be changed in a DBMS that fully supports data independence.

Answer 36

mappings

Question 37

Types of DBMS Languages

Answer 37

Data Definition Language (DDL) Data Manipulation Language (DML) Low Level or Procedural Languages

Question 38

Used by the DBA and database designers to specify the conceptual schema of a database

Answer 38

Data Definition Language (DDL)

Question 39

In many D B M S s, the D D L is also used to define ______ and ______ schemas

Answer 39

internal and external

Question 40

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

Answer 40

storage definition language (internal) View definition language (external)

Question 41

Used to specify database retrievals and updates

Answer 41

Data Manipulation Language (DML)

Question 42

DML commands (data sublanguage) can be embedded in a __________ (host language), such as COBOL, C, C++, or Java.

Answer 42

general-purpose programming language

Question 43

A library of ______ can also be provided to access the DBMS from a programming language

Answer 43

functions

Question 44

stand-alone DML commands can be applied directly (called a ___________).

Answer 44

query language

Question 45

Types of DML

Answer 45

High Level or Non-procedural Language Low Level or Procedural Language

Question 46

High Level or Non-procedural Language also called

Answer 46

declarative languages

Question 47

Are “set”-oriented and specify what data to retrieve rather than how to retrieve it

Answer 47

High Level or Non-procedural Language

Question 48

Retrieve data one record-at-a-time

Answer 48

Low Level or Procedural Language

Question 49

Constructs such as looping are needed to retrieve multiple records, along with positioning pointers

Answer 49

Low Level or Procedural Language

Question 50

Types of DBMS Interfaces

Answer 50

Stand-alone query language interfaces Programming interfaces User-friendly interfaces Mobile interfaces

Question 51

DBMS Programming Language Interfaces

Answer 51

Embedded Approach Procedural Call Approach Database Programming Language Approach Scripting Languages

Question 52

SQL is embedded directly in the source code of a host language (C, C++, Java, etc.), often requiring a precompiler.

Answer 52

Embedded Approach

Question 53

Use of database APIs to interact with the database. SQL commands are passed as parameters to functions or methods.

Answer 53

Procedural Call Approach

Question 54

A specialized language (often SQL with procedural extensions) that allows seamless integration of SQL and programming logic.

Answer 54

Database Programming Language Approach

Question 55

High-level scripting languages like PHP or Python use database connectors/modules to interact with databases.

Answer 55

Scripting languages

Question 56

User-Friendly DBMS Interfaces

Answer 56

Menu-based (web-based) Forms-based Graphics-based Natural language Combinations

Question 57

Other DBMS Interfaces

Answer 57

Natural language Speech Web Browser Parametric interfaces

Question 58

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

Answer 58

Data dictionary/repository

Question 59

is accessed by DBMS software and users/DBA.

Answer 59

Active data dictionary

Question 60

is accessed by users/DBA only.

Answer 60

Passive data dictionary

Question 61

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

Answer 61

Centralized DBMS

Question 62

In a centralized DBMS, User can still connect through a remote terminal – however, all processing is done at ________

Answer 62

centralized site

Question 63

Specialized Servers with Specialized functions and Clients can access the specialized servers as needed

Answer 63

Basic 2-Tier Client-Server Architectures

Question 64

What are the types of Specialized Servers with Specialized functions

Answer 64

Print server File server DBMS server Web server Email server

Question 65

Provide appropriate interfaces through a client software module to access and utilize the various server resources.

Answer 65

Clients

Question 66

Clients may be ____ machines or P C s or Workstations with disks with only the client software installed.

Answer 66

diskless

Question 67

Connected to the servers via some form of a network.

Answer 67

Clients

Question 68

Provides database query and transaction services to the clients

Answer 68

DBMSServer

Question 69

Relational DBMS servers are often called ________

Answer 69

SQL servers, query servers, or transaction servers

Question 70

Applications running on clients utilize an __________ to access server databases via standard interface

Answer 70

Application Program Interface (API)

Question 71

Applications running on clients utilize an Application Program Interface (A P I) to access server databases via standard interface such as?

Answer 71

ODBC: Open Database Connectivity standard JDBC: Java programming access

Question 72

Client and server must install appropriate ______ and ______ software for ODBC or JDBC

Answer 72

client and server module

Question 73

A client program may connect to several DBMSs, sometimes called the _______

Answer 73

data sources

Question 74

In general, data sources can be ____ or other non-DBMS software that manages data.

Answer 74

files

Question 75

It is common for web applications regarding client and server

Answer 75

Three Tier Client-Server Architecture

Question 76

Three Tier Client-Server Architecture has an intermediate layer called

Answer 76

Application Server or Web Server

Question 77

Stores the web connectivity software and the business logic part of the application used to access the corresponding data from the database server

Answer 77

Intermediate Layer

Question 78

Acts like a conduit for sending partially processed data between the database server and the client.

Answer 78

Intermediate Layer

Question 79

Variations of Distributed DBMSs (DDBMSs)

Answer 79

Homogeneous DDBMS Heterogeneous DDBMS Federated or Multidatabase Systems Distributed Database Systems

Question 80

Participating Databases are loosely coupled with high degree of autonomy.

Answer 80

Federated or Multidatabase Systems

Question 81

Distributed Database Systems have now come to be known as _______ database systems

Answer 81

client-server based

Question 82

organizes data in a tree-like structure, where each record has a single parent and potentially many children.

Answer 82

Hierarchical data model

Question 83

similar to the hierarchical model but allows each child node to have multiple parent nodes

Answer 83

Network Data Model

Question 84

organizes data into tables (relations), which consist of rows (tuples) and columns (attributes)

Answer 84

Relational Data Model

Question 85

integrates concepts from object-oriented programming (OOP) into databases

Answer 85

Object-Oriented Data Model

Question 86

combines the strengths of both relational and object-oriented models.

Answer 86

Object-Relational Data Model