lec 1

Question 1

Record

Answer 1

• identifiable collection of data elements
• some collection of attributes that describe some entity or event
• basic unit of storage that a user recognizes

Question 2

file

Answer 2

named collection of occurences of logical records which may be of more than one logical record type; a set of application record values pertaining to one or more record formats

Question 3

Field

Answer 3

smallest meaningful unit of information of interest

Question 4

Sequential access

Answer 4

method of using tape storage

Question 5

record key

Answer 5

data element chosen to record the data set is called the key

Question 6

Direct Access

Answer 6

The first access method designed to make use of the ability to quickly go to any location on a disk
- Records stored in fixed locations based on the values of key fields that can be directly mapped to a physical location on a disk
(records are accessed in their original location)

Question 7

Indexed sequential access

Answer 7

optimized access speed with storage space utilization as a major improvement over direct access
- Records stored in FCFS manner are quickly accessed using an inex of pointers from record keys to the locations of the records (index resorted each time it is updated)
(records are accessed in their original location)

Question 8

file based system

Answer 8

a collection of application programs that perform services for the end users, such as the production of reports

Question 9

File based approach

Answer 9

typically bottom up
to meet the needs of a small group of users
often on local departmental systems

Question 10

Disadvantages of file based approach

Answer 10

• seperation and isolation of data(data sharability)
• duplication of data (data inconsistency)
• data dependence (data structures highly independent)(data evolvability)
• incompatible file formats (programs and languages) (data sharability)
• no standard for queries(you have to develop your own

Question 11

database

Answer 11

a shared collection of logically related data, designed to meet the information needs of an organization

Question 12

Database approach advantages

Answer 12

Data integrity - ensuring the correctness, protection and security of the data
data sharability - ensures data can be shared between applications and users on a need to know basis
data availability - data can be accessed when and where it’s needed
data evolvability - ensures database can be modified to meet changing needs
Avoids redundency - where multiple copies of data are collected and used independently

Question 13

disadvantages of database approach

Answer 13

• complexity - highly trained staff needed, organizational infrastructure to handle costs, evolutionary planning, hardware and software support
• large DBMS have high cost and are closed source
• cost of conversion
• Performance - additions may slow down applications
• high impact of failure - department or organization

Question 14

To create a successful database

-

Answer 14

it takes understanding the data and needs of users

Question 15

Ansi-sparc architecture

Answer 15

To seperate each users view of the database, from the way the database is physically represented
- database administrator - controls physical internal and conceptual structures

Question 16

Ansi-sparc arcitecture

Answer 16

• external level - user’s view of the database, that part of the database that is relevant to each user
• conceptual level - community view of the database, what data is stored in the database and the relationships(complete set of data)
• internal level - describes data stored on computer, physical representation on computer (IT only)
• physical organization of data - managed by opereating system under DBMS

Question 17

schema

Answer 17

description of database (not in physical organization of data level )

Question 18

mapping

Answer 18

consistent correspondence between mapping at different levels

Question 19

instance

Answer 19

the data in a database at a particular instance in time

Question 20

independence

Answer 20

• immunity of one level of a database to changes at a lower level

Question 21

data definition language

Answer 21

language that allows the dba or user to describe and name entities, attributes and any relationships required for the application together with any associated integrity and security constraints

Question 22

data manipulation language

Answer 22

language that provides a set of operations to support the basic data manipulation operations on the data held in the database

Question 23

procedural dml

Answer 23

a language that allows the user to tell the system what data is needed and exactly how to retrieve the data

Question 24

non-procedural dml

Answer 24

a language the allows the user to state what data is needed rather than how it is to be retrieved

Question 25

fourth generation languages

Answer 25

non-procedural languages that typically include a number of tools to help quickly develop applications
- can limit the developers freedom

Question 26

basic data processing functionality

Answer 26

• data storage retrieval and update (DML)

- user-accessible catalog (DDL)

Question 27

Business integrity supporting functionality

Answer 27

transaction support, concurrency control services, recovery services, authorization services, support for data communication

Question 28

transaction support

Answer 28

to ensure all or no parts of a transaction are processed

Question 29

concurrency control services

Answer 29

to ensure updates are completed before begin updated

Question 30

recovery services

Answer 30

to repair damages to db

Question 31

authorization services

Answer 31

to protect the database from unauthorized accessing

Question 32

support for data communication

Answer 32

support decentralized access by workers and clients

Question 33

DB administration functionality

Answer 33

integrity services
services to promote data independence
utility services

Question 34

integrity services

Answer 34

to assist in evolving the database

Question 35

utility services

Answer 35

allow tuning of the data

Question 36

Client server architecture

server program

Answer 36

manages database, maintains system catalog, accepts and processes database requests from client, checks authorization and complaints, provides concurrency and recovery, performs query/update processing and transmits response to clients

Question 37

client server architecture

Answer 37

manages the user interface, processes the application logic, accepts and checks syntax of user input, generates database requests and transmits to server, passes response back to user

Question 38

electronic data exchange

Answer 38

automated exchange of any predefined and structured data for business purposes among information systems of two or more parties

Question 39

Business operational view

Answer 39

involves standardized data elements
used by user communities
to produce open-edi scenarios
registered by a registration authority

Question 40

functional service view

Answer 40

involves standardization communications and db technologies
used by it designers and it implementers
combined with oped-eid scenarios
to enable the execution of open-edi transactions

Question 41

open-edi scenario

Answer 41

formal specification of a class of business transactions having the same goal

Question 42

Business transaction

Answer 42

“a predefined set of activities and/or processes of parties which is initiated by a party to accomplish an explicitly shared business goal and terminated upon recognition of one of the agreed conclusions by all parties although some of the recognition may be implicit.”