Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill Chapter 12: Databases

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 12-2 McGraw-Hill Introduction to Databases Like a library, secondary storage is designed to store informationLike a library, secondary storage is designed to store information End users need to understandEnd users need to understand –How such stored information is organized using data field, records, files and databases –The different types of databases and structures Competent end users need to be able to find information that is stored in databasesCompetent end users need to be able to find information that is stored in databases

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 12-3 McGraw-Hill Data Examples of data includeExamples of data include –Facts or observations about people, places, things, and events –Audio, music, photographs, and video Two ways to view dataTwo ways to view data –Physical view –Logical view

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 12-4 McGraw-Hill Data Organization CharacterCharacter FieldField RecordRecord FileFile TableTable DatabaseDatabase Key FieldKey Field Batch Versus Real-Time ProcessingBatch Versus Real-Time Processing

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 12-5 McGraw-Hill Key Field Unique identifier also known as primary fieldUnique identifier also known as primary field Common examplesCommon examples –Social Security Number –Student Identification Numbers –Employee Identification Numbers –Part Numbers –Inventory Numbers

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 12-6 McGraw-Hill Batch Processing Batch processingBatch processing –Data is collected over a period of time and the processing happens later all at one time

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 12-7 McGraw-Hill Real-Time Processing Real-time processingReal-time processing –Also known as online processing because it happens immediately during the transaction

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 12-8 McGraw-Hill Databases Collection of integrated dataCollection of integrated data –Logically related files and records Databases address data redundancy and data integrityDatabases address data redundancy and data integrity Need for databasesNeed for databases Database managementDatabase management

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 12-9 McGraw-Hill Need for Databases SharingSharing SecuritySecurity Avoid Data duplicationAvoid Data duplication Data integrityData integrity

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You McGraw-Hill Database Management DBMS engineDBMS engine Data definition subsystemData definition subsystem –Data dictionary Data manipulation subsystemData manipulation subsystem –Query-by-example –Structured query language (SQL) Application generation subsystemApplication generation subsystem Data administration subsystemData administration subsystem

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You McGraw-Hill DBMS Structure DBMS programs are designed to work with data that is logically structured or arrangedDBMS programs are designed to work with data that is logically structured or arranged Data models define rules and standards for data in a databaseData models define rules and standards for data in a database Five common data models areFive common data models are –Hierarchical database Hierarchical databaseHierarchical database –Network database Network databaseNetwork database –Relational database Relational databaseRelational database –Multidimensional database Multidimensional databaseMultidimensional database –Object-oriented database Object-oriented databaseObject-oriented database

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You McGraw-Hill Hierarchical Database Fields or records are structured in nodesFields or records are structured in nodes Nodes are points connected like branchesNodes are points connected like branches One parent per node; a parent has several child nodes (one-to-many relationship)One parent per node; a parent has several child nodes (one-to-many relationship) Return

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You McGraw-Hill Network Database Hierarchical node arrangementHierarchical node arrangement Each child node may have more than one parent node (many-to-many relationship)Each child node may have more than one parent node (many-to-many relationship) Additional nodes are called pointersAdditional nodes are called pointers Nodes can be reached through multiple pathsNodes can be reached through multiple paths Return

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You McGraw-Hill Relational Database Data stored in table called a relationData stored in table called a relation Tables consist of rows and columnsTables consist of rows and columns Tables related via a common data itemTables related via a common data item Return

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You McGraw-Hill Multidimensional Database A variation and an extension of the relational model to include additional dimensions, sometimes called a data cubeA variation and an extension of the relational model to include additional dimensions, sometimes called a data cube Good for representing complex relationshipsGood for representing complex relationships Advantages over relationalAdvantages over relational –Conceptualization –Processing speed Return

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You McGraw-Hill Object-Oriented Database Works with unstructured dataWorks with unstructured data –Photographs –Audio –Video Objects contain both data and instructionsObjects contain both data and instructions Organize using objects, classes, entities, attributes, and methodsOrganize using objects, classes, entities, attributes, and methods Return

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You McGraw-Hill Types of Databases IndividualIndividualIndividual Company or sharedCompany or sharedCompany or sharedCompany or shared DistributedDistributedDistributed CommercialCommercialCommercial

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You McGraw-Hill Individual Databases Also called a microcomputer databaseAlso called a microcomputer database Integrated file collection for one person usually under the person’s direct controlIntegrated file collection for one person usually under the person’s direct control Generally stored on the user’s hard-disk drive or on a LAN file serverGenerally stored on the user’s hard-disk drive or on a LAN file server Return

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You McGraw-Hill Company or Shared Databases Usually stored on a central database server and managed by a database administratorUsually stored on a central database server and managed by a database administrator Users throughout a company can access the database through the company’s networksUsers throughout a company can access the database through the company’s networks Return

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You McGraw-Hill Distributed Databases Database is located in a place or places other than where users are locatedDatabase is located in a place or places other than where users are located Typically, database servers on a client/server network provide the link between users and the distant dataTypically, database servers on a client/server network provide the link between users and the distant data Return

Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You McGraw-Hill Commercial Databases Generally an enormous database developed by an organization to cover particular subjectsGenerally an enormous database developed by an organization to cover particular subjects Access is offered to the public or selected outside individuals for a feeAccess is offered to the public or selected outside individuals for a fee Most commercial databases are designed for organizational and individual useMost commercial databases are designed for organizational and individual use Also referred to as information utilities or data banksAlso referred to as information utilities or data banks Return