File Organization Terms and Concepts
• Bit:Bit: Smallest unit of data; binary digit Smallest unit of data; binary digit (0,1)(0,1)
• Byte:Byte: Group of bits that represents a Group of bits that represents a single charactersingle character
• Field:Field: Group of words or a complete Group of words or a complete numbernumber
ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT
• Record:Record: Group of related fieldsGroup of related fields• File:File: Group of records of same typeGroup of records of same type• Database:Database: Group of related filesGroup of related files
• Entity:Entity: Person, place, thing, event about Person, place, thing, event about which information is maintainedwhich information is maintained
• Attribute:Attribute: Description of a particular entity Description of a particular entity
• Key field:Key field: Identifier field used to retrieve, Identifier field used to retrieve, update, sort a recordupdate, sort a record
File Organization Terms and ConceptsORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT
Data Hierarchy in a Computer System
Figure 7-1
ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT
THE DATABASE APPROACH TO DATA MANAGEMENT
DBMS - a software that permits DBMS - a software that permits
Database Management System (DBMS)
to centralize data,to centralize data,
manage them efficiently,manage them efficiently,
provide access to data by application programprovide access to data by application program
acts as an interface between application program & data fileacts as an interface between application program & data file
Database- Database- a collection of data organized to a collection of data organized to serve many applications efficiently by serve many applications efficiently by centralizing the data and minimizing centralizing the data and minimizing redundant data redundant data
THE DATABASE APPROACH TO DATA MANAGEMENT
Database Management System (DBMS)Application
ProgramsDBMS Data file
Pay roll
Software
Oracle
8i
D:\database\employee.ora
HRM
Software
Provident Fund
Management
Software
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
THE DATABASE APPROACH TO DATA MANAGEMENT
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 ServerMS-Access, MS-Visual FoxProMS-Access, MS-Visual FoxPro
THE DATABASE APPROACH TO DATA MANAGEMENT
• Entity-relationship diagram:Entity-relationship diagram: Methodology Methodology for documenting databases illustrating for documenting databases illustrating relationships between database entitiesrelationships between database entities
• Normalization:Normalization: Process of creating small Process of creating small stable data structures from complex groups stable data structures from complex groups of dataof data
CREATING A DATABASE ENVIRONMENT
Designing Databases
The Orders to ItemsSold relationship enforces referential integrity.
One Order can list many ItemsSold.
Data warehouseData warehouse
• Supports reporting and query toolsSupports reporting and query tools
• Stores current and historical data Stores current and historical data
• Consolidates data for management analysis Consolidates data for management analysis and decision makingand decision making
Data Warehousing and Datamining
DATABASE TRENDS
Components of a Data Warehouse
DATABASE TRENDS
DataminingDatamining
• Tools for analyzing large pools of data Tools for analyzing large pools of data
• Find hidden patterns and infer rules to Find hidden patterns and infer rules to predict trendspredict trends
Data Warehousing and DataminingDATABASE TRENDS
Top Related