Chapter 1

Question 1

Data

Answer 1

know facts that can be recorded and have implicit meaning

Question 2

Database

Answer 2

collection of related data
has implicit properties:
represents aspects of real world
changes in mini-world reflected in the database
logically coherent, aspect of order
designed, built, populated for a specific purpose

Question 3

DBMS

Answer 3

Database Management System
collection of related data and programs that enable users to create and maintain a database
facilities process of: defining, constructing, manipulating, and sharing databases among users and applciations

Question 4

DDL

Answer 4

Data Definition Language

Question 5

Meta-deta

Answer 5

database definition/ descriptive information

stored in DBMS catalog

Question 6

DML

Answer 6

Data Manipulation Language:

Query/update etc

Question 7

Populating Database

Answer 7

Inserting data to reflect the minworld

Question 8

Application Program

Answer 8

Access database by sending queries to DBMS

Question 9

Query

Answer 9

Causes some date to be retrieved

Question 10

Transaction

Answer 10

May cause some data to be read and some data to be written into the database

Question 11

Protecting a Database

Answer 11

System Protection: protect against hardware or software malfunction(crashes…)
Security Protection: protect against unauthorized/malicious access

Question 12

IS

Answer 12

Information System:

Question 13

Traditional File Processing

Answer 13

Each user defines and implements the files needed for a specific software application
Disadvantages:
Uncontrolled Redundancy & inconsistency: no supervision to coordinate data operations
Poor Enforcement of Standards: different formats…
Limited Data Sharing
Program-Data Dependency: any change to structures causes change in all programs accessing that file

Question 14

Database Approach Characteristics

Answer 14

Self-describing nature of a database system
Insulation between programs and data, and data abstraction
Support of multiple views of the data
Sharing of data and multi user transaction processing
Program-data independence: structure of data files is stored in DBMS catalog separate from access programs
Program-operation independence: some types of database systems enable definitions of operations on data as part of database definitions
Operations:
Interface(signature): includes operation name and data type of its arguments
Implementation(method) can be changed without affecting the interface

Question 15

Data abstraction

Answer 15

Characteristics that allow program-data independence and program-operation independence

Question 16

Data model

Answer 16

type of data abstraction used to provide conceptual representation
hides implementation and storage details

Question 17

OLTP

Answer 17

Online transaction processing

Ensure that concurrent transactions operate correctly and efficiently

Question 18

DBMS Properties

Answer 18

Isolation property:
Each transaction appears to execute in isolation from other transactions
Atomicity property:
Either all database operations in a transaction or none are

Question 19

DBA

Answer 19

Database Administrator
Database environment has two main resources:
database itself
DBMS and related software
DBA is responsible for:
authorizing access to the database
coordinating and monitoring use
acquiring software and hardware resources as needed

Question 20

Database designer

Answer 20

most tasks occur before database implemented
responsible for:
identifying data to be stored in database
choosing appropriate structure
communicating with all prospective DB users to determine requirements
create a design to meet requirements

Question 21

End Users

Answer 21

People whose job requires access to the database
Categories:
casual end user
naive/parametric end user
sophisticated end user
standalone end user

Question 22

Casual End Users

Answer 22

Occasionally access database, need different information each time

Question 23

Naive/Parametric End Users

Answer 23

Make up a sizable portion of database end users
Constantly querying/updating database
Use canned transactions

Question 24

Sophisticated End Users

Answer 24

Write sophisticated database applications that do not fin into the tradition data-processing framework
Thoroughly familiarize themselves with DBMS facilities

Question 25

System Analysts

Answer 25

Determine requirements of end users | Develop specifications for standard canned transactions

Question 26

Application Programmers

Answer 26

Implement specifications developed by analysts | Test, debug, document, maintain canned transactions

Question 27

DBMS Advantages

Answer 27

Data normalization: Stores each logical item in only one place, saves space Denationalization: Placing all the data together, no searching multiple files Restricting unauthorized access: Security and authorization subsystem Privileged software(controlling accounts) Efficient execution: Efficient search techniques: efficient query process Providing backup and recovery: Helps when system failure etc occurs Providing multiple user interfaces: Different types of users using same data base Representing complex relationships among data:

Question 28

When not to use a DBMS

Answer 28

Simple application that doesn't change Real-time requirements that might not be met Embedded systems with limited storage capacity No multiple-user access to data

Question 29

Data abstraction

Answer 29

Suppression of details of data organization and storage Highlighting essential features Basic Operation: get/query... Dynamic aspect/behavior: calculate from data

Question 30

Entity

Answer 30

Represents a real world object or concept: employee thing

Question 31

Attribute

Answer 31

Further describes an entity

Question 32

Relationship (among two+ entities)

Answer 32

Represents an association among the entities one-to-many (1:M) many-to-many (M:N)

Question 33

Relational data model

Answer 33

Represents a database as a collection of tables where each table can be stored as a separate file

Question 34

Object data model

Answer 34

Defines a database in terms of objects, their properties, and operations

Question 35

XML data model

Answer 35

Data is represented as elements (using tags) and data can be nested to create complex hierarchical structures

Question 36

Database Schema

Answer 36

Description of a database which is specified during database design, doesn't change frequently

Question 37

Schema Construct

Answer 37

A component of the schema or an object within the schema

Question 38

Database state

Answer 38

"extension of the schema" | each schema construct has its own current set of instances

Question 39

Schema States

Answer 39

Empty State: empty state (no data) Initial State: Populated/ loaded with initial data Valid State: Satisfies structure and constraints specified in the schema

Question 40

DDL

Answer 40

Data definition language Language used to define database schemas DBMS will use a DDL compiler to process DDL statements to identify description of the schema constructs and store the schema description in the DBMS catalog

Question 41

DML

Answer 41

Data Manipulation Language | A language used to manipulate data

Question 42

SDL

Answer 42

Storage definition language | Specifies the internal schema

Question 43

VDL

Answer 43

View definition language | Specifies user views and their mappings to conceptual schema

Question 44

ODBC

Answer 44

Open Database Connectivity