CHAPTER 1 MODULE Flashcards
raw, unprocessed facts
DATA
processed data to make a“meaningful context”
INFORMATION
collected/ collection of related data
DATABASE
complete description of database / The database definifiton
META-DATA
duplication of data or storing of the same information in more than one place.
REDUNDANCY/ DATA REDUNDANCY
all data are stored in one place to reduce redundancy.
SINGLE REPOSITORY
4 PROBLEMS THAT IS CAUSED BY REDUNDANCY
1.Redundant Storage
2.Update Anomalies
3.Insertion Anomalies
4.Deletion Anomalies
-a system to manage a database use to create, maintain, and access database “storing” and “retrieval” of data
- set of programs that allows users to create and maintain the database.
DATABASE MANAGEMENT SYSTEM
- part of the program that actually stores and retrieves data.
DATABASE ENGINE
4 functionalities
- Define
- Construct
- Manipulate
- Share
specifying the data type, structure, constraints for the data to be stored.
DEFINE
process of storing the data on some storage medium
CONSTRUCT
Querying the database to retrieve specific data, updating database and generating reports
MANIPULATE
a statement requesting the retrieval of info.
QUERY
allows multiple users and programs to access the database concurrently.
SHARE
PROPERTIES OF DATABASE
- A database represents some aspects of the real world (miniworld).
2.A database is a logically coherent (should be related) collection of data with some inherent meaning. - A database is designed, built, and populated with data for a specific purpose.
write the queries or programs
USERS/ PROGRAMMERS
process the queries or programs
DBMS SOFTWARE
CHARACTERISTICS OF DBMS
1.Self describing Nature of DBMS
2.Insulation between Programs and Data, & Data Abstraction
3.Support of Multiple Views of the Data
4.Sharing of Data and Multi-user Transaction Processing
2.Insulation between Programs and Data, & Data Abstraction
if there is a change in the structure of data, then the program changes too.
Traditional File Processing
Insulation between Programs and Data, & Data Abstraction
no need to change the program if there is a change in the structure of data (data program independence) —characteristic is “Data Abstraction”
DBMS Approach
Sharing of Data and Multi-user Transaction Processing
no multiple user, isolation
Concurrency Control
can only be answered by a yes or no and it must happen in its entity or not at all
Atomicity
2 types of Database Users
- Actors on the Scene
- Workers behind the Scene
Who belongs to Actors on the scene?
1.Database Administrators
2.Database Designers
3.End Users
Who belongs to workers behind the scene?
Software Engineers
System Designers and Implementers
Tool Developers
Operators and Maintenance Personnel
whose jobs involve the day to day use of large database.
ACTORS ON THE SCENE
(Primary Resource)
Database
DBMS & Related Software
(Secondary Resource)
RESPONSIBILITIES of Database Administrators:
a)Administering primary and secondary resources.
b)Give access to users/ authorizing access to the database
c)Coordinating and Monitoring the use of database
d)Accountable when there is breach of security and when there is poor system response time.
e)Acquiring software and hardware resources as needed.
a)Identify the data to be stored in the database.
b)Choosing appropriate structure to represent and store data.
c)Communicating with end-users in order to know their requirements (database design)
Responsibilities of database designers
Require access to the database: querying ,Updating Generating reports
End Users
Categories of End Users
- Casual
- Naive/ parametric
- Sophisticated
- Stand-Alone
access the database occasionally
Casual End Users
constantly querying and updating the database
Naive/Parametric End Users
standard types of queries and updates
canned transactions
Engineers, scientists, business, analysts, and others who thoroughly familiarize themselves with the facilities of DBMS
Sophisticated End Users
maintain personal database using ready made program packages
Stand-Alone End Users
Determine the requirements of end users in order to develop specifications
System Analysts
Implement the specifications as programs to test, debug, document and maintain
Application Programmers
whose job is to maintain the database, not interested about the database itself.
WORKERS BEHIND THE SCENE
system analyst and application programmers
Software Engineers
design and implement DBMS modules and interface as a package.
System Designers and Implementer
design and implement tools
Tool Developers
To facilitate the database system design and use
Tool :Software Packages
responsible for the actual running and maintenance of the software.
Operators and Maintenance Personnel
ADVANTAGES OF DBMS
1.Compactness
2.Controlling Redundancy
3.Restricting Unauthorized Access
4.Providing Persistent Storage for Program Objects
5.Providing Storage Structures for Efficient Query Processing
6.Providing Backup and Recovery
7.Providing Multiple User Interface
8.Representing Complex Relationship Among Data
9.Enforcing Integrity Constraints
ADVANTAGES.
data are stored in a single repository
Compactness
wastage of storage and its inconsistency
Traditional File System
Controlling Redundancy
Traditional File System
DBMS Approach
- for security and authorization subsystem
- work of database administrators
Restricting Unauthorized Access
Providing Persistent Storage for Program Objects (AD)
Programs terminate _ Values of program Variables_ Discarded
TRADITIONAL
Program terminate_ Values of program variable_ Not discarded (stores object permanently) _ Persistent
DBMS Approach
responsible for efficient query and execution
Providing Storage Structures for Efficient Query Processing and Optimization Module
-When there is system failure
-Capable of doing recovery
Providing Backup and Recovery
4 Multiple User Interface
- Query Language
- Programming Language
- Forms
- Menu Driven Interface
Interface for casual end users.
Query Language
Interface for app programmer
Programming Language
Interface for naive/parametric
Forms
interface for stand alone
Menu-Driven Interface
simplest data constraints such as data types by the database designers.
Enforcing Integrity Constraints
DISADVANTAGES OF DBMS
1.Increased Complexity
2.Greater Impact of Failure
3.More Difficult Recovery
4.Large File Size
you need to master facilities
Increased Complexity
you need to master facilities
Increased Complexity
you need to master facilities
Increased Complexity
the more users of the DBMS, the greater the tendency for the system to fail
More Difficult Recovery
Data are stored in a “single repository” that requires a larger storage Space
4.Large File Size
