Transcript Session 7

SESSION 7
MANAGING
DATA
RESOURCES
ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT
File Organization Terms and Concepts
Field: Group of words or a complete
number
Record: Group of related fields
File: Group of records of same type
Database: Group of related files
ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT
File Organization Terms and Concepts
Data Hierarchy in a Computer System
Figure 7-1
ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT
File Organization Terms and Concepts
Entity: Person, place, thing, event about
which information is maintained
Attribute: Description of a particular
entity
Key field: Identifier field used to
retrieve, update, sort a record
ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT
File Organization Terms and Concepts
Entitities and Attributes
Figure 7-2
ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT
Problems with the Traditional File Environment
Data redundancy
Program-Data dependence
Lack of flexibility
Poor security
Lack of data-sharing and availability
THE DATABASE APPROACH TO DATA MANAGEMENT
Database Management System (DBMS)
• Creates and maintains databases
• Eliminates requirement for data definition
statements
• Acts as interface between application
programs and physical data files
• Separates logical and design views of data
THE DATABASE APPROACH TO DATA MANAGEMENT
TYPES OF DATABASES
Relational DBMS
• Represents data as two-dimensional tables
called relations
• Relates data across tables based on common
data element
• Examples: DB2, Oracle, MS SQL Server
THE DATABASE APPROACH TO DATA MANAGEMENT
Three Basic Operations in a Relational Database
• Select: Creates subset of rows that meet
specific criteria
• Join: Combines relational tables to provide
users with information
• Project: Enables users to create new tables
containing only relevant information
THE DATABASE APPROACH TO DATA MANAGEMENT
Three Basic Operations in a Relational Database
Figure 7-7
THE DATABASE APPROACH TO DATA MANAGEMENT
Hierarchical and Network DBMS
Hierarchical DBMS
• Organizes data in a tree-like structure
• Supports one-to-many parent-child
relationships
• Prevalent in large legacy systems
THE DATABASE APPROACH TO DATA MANAGEMENT
Hierarchical DBMS
Figure 7-8
THE DATABASE APPROACH TO DATA MANAGEMENT
Hierarchical and Network DBMS
Network DBMS
• Depicts data logically as many-to-many
relationships
THE DATABASE APPROACH TO DATA MANAGEMENT
Network DBMS
Figure 7-9
THE DATABASE APPROACH TO DATA MANAGEMENT
Hierarchical and Network DBMS
Disadvantages
Outdated
Less flexible compared to RDBMS
Lack support for ad-hoc and English
language-like queries
THE DATABASE APPROACH TO DATA MANAGEMENT
Object-Oriented databases
Object-oriented DBMS: Stores data and
procedures as objects that can be
retrieved and shared automatically
Object-relational DBMS: Provides
capabilities of both object-oriented and
relational DBMS
THE DATABASE APPROACH TO DATA MANAGEMENT
CREATING A DATABASE ENVIRONMENT
Designing Databases
Conceptual design: Abstract model of
database from a business perspective
Physical design: shows how the database is
actually arranged on direct access storage
devices.
THE DATABASE APPROACH TO DATA MANAGEMENT
CREATING A DATABASE ENVIRONMENT
Distributing databases
Stored in more than one physical location
Partitioned database
Duplicated database
DATABASE TRENDS
Multidimensional Data Analysis
On-line analytical processing (OLAP)
Multidimensional data analysis
Supports manipulation and analysis of
large volumes of data from multiple
dimensions/perspectives
DATABASE TRENDS
Data warehouse
Supports reporting and query tools
Stores current and historical data
Consolidates data for management
analysis and decision making
DATABASE TRENDS
Benefits of Data Warehouses
Improved and easy accessibility to
information
Ability to model and remodel the data
DATABASE TRENDS
Data mart
Subset of data warehouse
Contains summarized or highly focused
portion of data for a specified function or
group of users
DATABASE TRENDS
Datamining
Tools for analyzing large pools of data
Find hidden patterns and infer rules to
predict trends
DATABASE TRENDS
Databases and the Web
Database server
Computer in a client/server environment
runs a DBMS to process SQL statements
and perform database management tasks
Application server
Software handling all application
operations
DATABASE TRENDS
Linking Internal Databases to the Web
Figure 7-18