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ObjectivesObjectives Definition of termsDefinition of terms Explain growth and importance of databasesExplain growth and importance of databases Name limitations of conventional file Name limitations of conventional file
processingprocessing Identify categories of databasesIdentify categories of databases Explain advantages of databasesExplain advantages of databases Identify costs and risks of databasesIdentify costs and risks of databases List components of database environmentList components of database environment Describe evolution of database systemsDescribe evolution of database systems
DefinitionsDefinitions Database: organized collection of logically Database: organized collection of logically
related datarelated data Data: stored representations of meaningful Data: stored representations of meaningful
objects and eventsobjects and events Structured: numbers, text, datesStructured: numbers, text, dates Unstructured: images, video, documentsUnstructured: images, video, documents
Information: data processed to increase Information: data processed to increase knowledge in the person using the dataknowledge in the person using the data
Metadata: data that describes the properties Metadata: data that describes the properties and context of user dataand context of user data
Disadvantages of File Disadvantages of File ProcessingProcessing
Program-Data DependenceProgram-Data Dependence All programs maintain metadata for each file they useAll programs maintain metadata for each file they use
Duplication of DataDuplication of Data Different systems/programs have separate copies of the Different systems/programs have separate copies of the
same datasame data
Limited Data SharingLimited Data Sharing No centralized control of dataNo centralized control of data
Lengthy Development TimesLengthy Development Times Programmers must design their own file formatsProgrammers must design their own file formats
Excessive Program MaintenanceExcessive Program Maintenance 80% of of information systems budget80% of of information systems budget
Problems with Data Problems with Data DependencyDependency
Each application programmer must Each application programmer must maintain their own datamaintain their own data
Each application program needs to Each application program needs to include code for the metadata of each include code for the metadata of each filefile
Each application program must have its Each application program must have its own processing routines for reading, own processing routines for reading, inserting, updating and deleting datainserting, updating and deleting data
Lack of coordination and central controlLack of coordination and central control Non-standard file formatsNon-standard file formats
Problems with Data Problems with Data RedundancyRedundancy
Waste of space to have duplicate dataWaste of space to have duplicate data Causes more maintenance headachesCauses more maintenance headaches The biggest problem: The biggest problem:
When data changes in one file, When data changes in one file, could cause inconsistenciescould cause inconsistencies
Compromises Compromises data integritydata integrity
Use of Internet TechnologyUse of Internet Technology Networks and telecommunications, distributed databases, Networks and telecommunications, distributed databases,
client-server and 3-tier architecturesclient-server and 3-tier architectures Database ApplicationsDatabase Applications
Application programs used to perform database activities Application programs used to perform database activities (create, read, update, and delete) for database users(create, read, update, and delete) for database users
Components of the Components of the Database EnvironmentDatabase Environment
CASE ToolsCASE Tools – computer-aided software engineering – computer-aided software engineering RepositoryRepository – centralized storehouse of metadata – centralized storehouse of metadata Database Management System (DBMS)Database Management System (DBMS) – software for – software for
managing the databasemanaging the database DatabaseDatabase – storehouse of the data – storehouse of the data Application ProgramsApplication Programs – software using the data – software using the data User InterfaceUser Interface – text and graphical displays to users – text and graphical displays to users Data AdministratorsData Administrators – personnel responsible for – personnel responsible for
maintaining the databasemaintaining the database System DevelopersSystem Developers – personnel responsible for designing – personnel responsible for designing
databases and softwaredatabases and software End UsersEnd Users – people who use the applications and databases – people who use the applications and databases