Lecture 04 data resource management

DATA RESOURCE

MANAGEMENTPresented by:

Dr. Akhlas AhmedLecture # 04

Preston University

File Organization:Terms & Concept

Binary: means composed of two pieces or two parts and may refer to:

Mathematics:Binary number, a representation for numbers using only two digits

(0 and 1)Binary relation, a mathematical relation involving two elementsBinary function, a function in mathematics that takes two

argumentsComputingBinary file, composed of something other than human-readable textExecutable, a type of binary file that contains machine code for the

computer to executeBinary code, the digital representation of text and data

File Organization:Terms & Concept

Multiples of bits

Decimal

Value Metric

1000 kbit kilobit

10002 Mbit megabit

10003 Gbit gigabit

10004 Tbit terabit

10005 Pbit petabit

10006 Ebit exabit

10007 Zbit zettabit

10008 Ybit yottabit

Binary

Value JEDEC IEC

1024 Kbit kilobit Kibit kibibit

10242 Mbit megabit Mibit mebibit

10243 Gbit gigabit Gibit gibibit

10244 - - Tibit tebibit

10245 - - Pibit pebibit

10246 - - Eibit exbibit

10247 - - Zibit zebibit

10248 - - Yibit yobibitSee also: Nibble · Byte · Bit and Byte prefixes

Orders of magnitude of data

File Organization:Terms & Concept

• Bit: A bit is the basic unit of information in computing and digital communications. A bit can have only one of two values, and may therefore be physically implemented with a two-state device. The most common representation of these values are 0and1. The term bit is a contraction of binary digit.

Smallest unit of data; binary digit (0,1) Byte: Group of bits that represents a single

character Field: Group of words or a complete number

File Organization:Terms & Concept

Record: Group of related fields

File: Group of records of same type

Database: Group of related files

Data Hierarchy:in a Computer System

Figure 7-1

File Organization:Terms & Concept

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

Figure 7-2

Problems with the Traditional File Environment

Data redundancy Data redundancy occurs in database systems which have a field that is repeated in two or more tables.

o Program-Data dependence A Flow dependency, also known as a data dependency or true dependency or read-after-write (RAW), occurs when an instruction depends on the result of a previous instruction:1. A = 3 2. B = A 3. C = B

Lack of flexibility Poor security Lack of data-sharing and availability

Traditional File Processing

Figure 7-3

Database Management System (DBMS)

• Creates and maintains databasesCreates and maintains databases

• Eliminates requirement for data definition Eliminates requirement for data definition statementsstatements

• Acts as interface between application Acts as interface between application programs and physical data filesprograms and physical data files

• Separates logical and physical views of Separates logical and physical views of datadata

The Contemporary Database Environment

Figure 7-4

Components of DBMS

• Data definition language: Data definition language: Specifies Specifies content and structure of database and content and structure of database and defines each data elementdefines each data element

• Data manipulation language:Data manipulation language:Manipulates data in a databaseManipulates data in a database

• Data dictionary:Data dictionary: Stores definitions of Stores definitions of data elements, and data characteristicsdata elements, and data characteristics

Sample Data Dictionary Report

Figure 7-5

Types of Databases

• Relational DBMSRelational DBMS

• Hierarchical and Network DBMSHierarchical and Network DBMS

• Object-Oriented DatabasesObject-Oriented Databases

Relational DBMS

• Represents data as two-dimensional tables Represents data as two-dimensional tables called relationscalled relations

• Relates data across tables based on common Relates data across tables based on common data elementdata element

• Examples: DB2, Oracle, MS SQL ServerExamples: DB2, Oracle, MS SQL Server

Relational Data Model

Figure 7-6

Three Basic Operations in a Relational Database

• Select:Select: Creates subset of rows that meet Creates subset of rows that meet specific criteriaspecific criteria

• Join:Join: Combines relational tables to provide Combines relational tables to provide users with informationusers with information

• Project:Project: Enables users to create new tables Enables users to create new tables containing only relevant informationcontaining only relevant information

Three Basic Operations in a Relational Database

Figure 7-7

Hierarchical and Network DBMS

Hierarchical DBMSHierarchical DBMS

• Organizes data in a tree-like structureOrganizes data in a tree-like structure

• Supports one-to-many parent-child Supports one-to-many parent-child relationshipsrelationships

• Prevalent in large legacy systemsPrevalent in large legacy systems

Hierarchical DBMS

Figure 7-8

Hierarchical and Network DBMS

Network DBMSNetwork DBMS

• Depicts data logically as many-to-many Depicts data logically as many-to-many relationshipsrelationships

Network DBMS

Figure 7-9

Hierarchical and Network DBMS

Disadvantages

Outdated

Less flexible compared to RDBMS

Lack support for ad-hoc and English language-like queries

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

Querying Databases: Elements of SQL

Basic SQL Commands

SELECT: Specifies columns

FROM: Identifies tables or views

WHERE: Specifies conditions

Results of SELECT Statement

Results of Conditional Selection

137150

Door latchDoor seal

22.506.00

Projection from Joining PART and SUPPLIER Tables

Designing Databases

Conceptual design: Abstract model of database from a business perspective

Physical design: Detailed description of business information needs

Designing Databases

Entity-relationship diagram: Methodology for documenting databases illustrating relationships between database entities

Normalization: Process of creating small stable data structures from complex groups of data

CREATING A DATABASE ENVIRONMENT

CREATING A DATABASE ENVIRONMENT

CREATING A DATABASE ENVIRONMENT

Figure 7-15

An Normalized Relation of ORDER

Distributing Databases

Centralized database

Used by single central processor or multiple processors in client/server network

Distributing Databases

Distributed database

Stored in more than one physical location

Partitioned database

Duplicated database

Distributing Databases

Figure 7-16

Management Requirements for Database Systems

Key elements in a database environment:

Data Administration

Data Planning and Modeling Methodology

Database Technology and Management

Users

Management Requirements for Database Systems

Figure 7-17

Multidimensional Data Analysis

On-line analytical processing (OLAP)

Multidimensional data analysis

Supports manipulation and analysis of large volumes of data from multiple dimensions/perspectives

Multidimensional Data Model

Figure 7-18

Data Warehousing and Datamining

Data warehouse

Supports reporting and query tools

Stores current and historical data

Consolidates data for management analysis and decision making

Components of Data Warehouse

Figure 7-19

Data Warehouse and data mining

Data mart

Subset of data warehouse

Contains summarized or highly focused portion of data for a specified function or group of users

Data Warehouse and data mining

Datamining

Tools for analyzing large pools of data

Find hidden patterns and infer rules to predict trends

Benefits of Data Warehouse

Improved and easy accessibility to information

Ability to model and remodel the data

Database and the web

Hypermedia databaseHypermedia database

• Organizes data as network of nodesOrganizes data as network of nodes

• Links nodes in pattern specified by userLinks nodes in pattern specified by user

• Supports text, graphic, sound, video and Supports text, graphic, sound, video and executable programsexecutable programs

Database Trends

Figure 7-20

A Hypermedia Database

Database Trends

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

Databases and the Web

Database Trends

Figure 7-21

Linking Internal Databases to the Web

Thank You