chp2

Question 1

A set of concepts to describe the structure of a Database, the operations for manipulating them, and constraints.

Answer 1

data model

Question 2

used to define the DB structure

Answer 2

Constructs

Question 3

Constructs typically include………….. (and their data types)

Answer 3

elements

Question 4

Constructs typically include elements, group of elements, and……….among these groups

Answer 4

relationships

Question 5

………specify some restrictions on valid data, and they must be enforced at all times

Answer 5

constraints

Question 6

categories for data models:

Answer 6

physical, conceptual, implementation, and self describing data models

Question 7

which data model provides concepts that are close to the way users perceive data?

Answer 7

conceptual models

Question 8

which data model provides concepts that describe details of how data is stored in the computer?

Answer 8

physical models

Question 9

description of the data

Answer 9

Database schema

Question 10

a state that satisfies the structure and constraints of the database

Answer 10

Valid state

Question 11

the database (schema/ state) changes infrequently

Answer 11

schema

Question 12

T/F
the database state changes everytime the db is updated?

Answer 12

TRUE

Question 13

T/F
schema is also called an extension

Answer 13

FALSE, schema is also called an intension. whereas the state is also called an extension.

Question 14

three schema architecture defines DBMS at 3 levels:

Answer 14

internal, conceptual, and external schemas

Question 15

T/F
(The internal schema) describes structure and constraints for the whole database

Answer 15

false, conceptual schema

Question 16

T/F
(conceptual schema) describes physical storage structures and access paths

Answer 16

false, internal schema

Question 17

(logical/physical) data independence is the capacity to change the conceptual schema without having to change the external schemas

Answer 17

logical data independence

Question 18

T/F
when a schema at a lower level is changed, only the mappings between this schema and the higher level schemas need to be changed

Answer 18

TRUE, in a DBMS that fully supports data independence

Question 19

example of high level / non procedural language?

Answer 19

SQL

Question 20

Which language is used by DBA and database designers to specify the conceptual schema of a database?

Answer 20

Data definition language DDL

Question 21

also called a query language

Answer 21

Data manipulation language DML

Question 22

T/F
high level / non procedural languages specify what data to retrieve rather than how to retrieve it

Answer 22

TRUE.

Question 23

menu based, form based, etc are examples of

Answer 23

User friendly interfaces

Question 24

point and click, drag and drop, etc are examples for

Answer 24

graphic based interface

Question 25

used to store schema descriptions and other information such as design decisions

Answer 25

data dictionary / repository

Question 26

(Active/Passive) data dictionary is accessed by DBMS software and users/DBA.

Answer 26

Active. Passive is accessed by users/DBA only

Question 27

combines everything into a single system

Answer 27

Centralized DBMS

Question 28

Intermediate layer in a three-tier client-server architecture is also called............... or................

Answer 28

Application server or Web server

Question 29

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

Answer 29

The intermediate layer

Question 30

T/F three-tier client-server architecture can enhance security

Answer 30

TRUE

Question 31

T/F a data dictionary utility is similar to the system catalog, but the system catalog includes a wider variety of information and is accessed mainly by users and DBMS software

Answer 31

FALSE

Question 32

T/F Every time we insert a record or change the value of a data item in a record, we change the schema of a DB into another schema

Answer 32

FALSE

Question 33

T/F In a three-tier schema architecture, database servers hold the business logic

Answer 33

FALSE

Question 34

T/F a non procedural DML can be used on its own to specify complex database operations

Answer 34

TRUE

Question 35

T/F When a new user is added to the database, the database schema is updated

Answer 35

FALSE

Question 36

T/F Queries and transactions serve the same purpose and are interchangeable in database processing

Answer 36

FALSE

Question 37

In a two-tier architecture, which system component provides query and transaction functionalities? (client/server/ application server)

Answer 37

Server