1 R. Ching, Ph.D. MIS Dept. California State University, Sacramento Week 2 September 7 File-based Systems and DatabaseFile-based Systems and Database Database EnvironmentDatabase Environment

2 R. Ching, Ph.D. MIS Dept. California State University, Sacramento What is Database? Definition: "A shared collection of logically related data, and a description of this data, designed to meet the information needs of the organization."Definition: "A shared collection of logically related data, and a description of this data, designed to meet the information needs of the organization." Data repositoryData repository Customer transactions Inventory Operating expenses Payroll Vendors Management system controls access

3 R. Ching, Ph.D. MIS Dept. California State University, Sacramento Traditional File-Based System Definition: "A collection of application programs that perform services for the end-users such as the production of reports. Each program defines and manages its own data."Definition: "A collection of application programs that perform services for the end-users such as the production of reports. Each program defines and manages its own data." Payroll Operating expenses Customer transactions VendorsInventory ProgramProgramProgramProgramProgram ReportReportReportReportReport One file, one application

4 R. Ching, Ph.D. MIS Dept. California State University, Sacramento For example…

5 R. Ching, Ph.D. MIS Dept. California State University, Sacramento Invoice No.

6 R. Ching, Ph.D. MIS Dept. California State University, Sacramento Stereos To Go Invoice No. Date: / / Account No. Item Number Product Description/Manufacturer Qty Price Product Code Date Shipped: / / Customer: Address: CityStateZip Code Invoice Customer Invoice Items purchased on the Invoice Products and Manufacturers Invoice Anatomy of an Invoice

7 R. Ching, Ph.D. MIS Dept. California State University, Sacramento Stereos To Go Invoice No. Date: / / Account No. Item Number Product Description/Manufacturer Qty Price Product Code Date Shipped: / / Customer: Address: CityStateZip Code Invoice Customer Invoice Items purchased on the Invoice Products and Manufacturers Invoice Anatomy of an Invoice William Tell Street FDInvoice-File. 01Invoice-Record. 05Invoice-numberPIC X(5). 05Invoice-datePIC X(6). 05Cust-account-numberPIC X(10). 05Cust-First-NamePIC X(15). 05Cust-Last-NamePIC X(20). 05Cust-AddressPIC X(30). FDInvoice-File. 01Invoice-Record. 05Invoice-numberPIC X(5). 05Invoice-datePIC X(6). 05Cust-account-numberPIC X(10). 05Cust-First-NamePIC X(15). 05Cust-Last-NamePIC X(20). 05Cust-AddressPIC X(30).

8 R. Ching, Ph.D. MIS Dept. California State University, Sacramento Traditional File-Based System Invoice Program Invoices Customer Account Program Account Report Customer Mailings Program Mailing List CustomerOrders “A collection of application programs that perform services for the end users such as the production of reports. Each program defines and manages its own data.” Customer Mailing List Customer Accounts File

9 R. Ching, Ph.D. MIS Dept. California State University, Sacramento Data Redundancy Customer Order FileCustomer Order File –Invoice number –Customer account number –Customer name, address, city, state, zip code –Order date –Product code, product description, price, unit Customer Account FileCustomer Account File –Account Number –Customer name, mailing address, city, state, zip code Customer Mailing List FileCustomer Mailing List File –Customer name, mailing address, city, state, zip code

10 R. Ching, Ph.D. MIS Dept. California State University, Sacramento File-Based Systems Records contain logically related dataRecords contain logically related data Limitations:Limitations: –Separation and isolation of data (one file, one program) –Duplication of data Loss of data integrity - uncertainty of the correct version of data and no consistencyLoss of data integrity - uncertainty of the correct version of data and no consistency –Data dependence - application program defines the data –Incompatibility of file formats –Fixed queries/proliferation of application programs - little flexibility in meeting changing information needs

11 R. Ching, Ph.D. MIS Dept. California State University, Sacramento Database Data and Data Data and DataDefinitions Applications “A shared collection of logically related data (and a description of this data), designed to meet the information needs of an organization.”“A shared collection of logically related data (and a description of this data), designed to meet the information needs of an organization.” Separation Central Repository

12 R. Ching, Ph.D. MIS Dept. California State University, Sacramento Data Abstraction Separation between the data’s structure (definition) and the application programsSeparation between the data’s structure (definition) and the application programs FD Master-File. 01 Master-Record. 05 IDPIC X(10). 05 Customer-Fname PIC X(25).... Tightly binds the data file and program COBOL

13 R. Ching, Ph.D. MIS Dept. California State University, Sacramento Tightly binds the data file and program Data Abstraction Separation between the data’s structure (definition) and the application programsSeparation between the data’s structure (definition) and the application programs FD Master-File. 01 Master-Record. 05 IDPIC X(10). 05 Customer-Fname PIC X(25).... COBOL Data Output Program

14 R. Ching, Ph.D. MIS Dept. California State University, Sacramento Data Abstraction Separation between the data’s structure (definition) and the application programsSeparation between the data’s structure (definition) and the application programs Data and Data Definitions Applications Central Repository DBMS Application programs can be run on either the clients or server

15 R. Ching, Ph.D. MIS Dept. California State University, Sacramento Organizing Data Entity - distinct object (i.e., person, place, thing, concept or event)Entity - distinct object (i.e., person, place, thing, concept or event) Attribute - describes some aspect of the entity (object)Attribute - describes some aspect of the entity (object) –Property of the entity Relationship - association between entitiesRelationship - association between entities Customers Account_number Name Address Purchases Invoice_number Account_number Purchase_date Attributes Relationship EntityEntity

16 R. Ching, Ph.D. MIS Dept. California State University, Sacramento Stereos to Go Database Customer Orders Order Items Manufacturers Products DBMS Management Queries Application Programs Other Software DDLDDL DMLDML Controlled accessControlled access Central Repository (Organizational resource) Single Access Point Multitude of Applications

17 R. Ching, Ph.D. MIS Dept. California State University, Sacramento Components of a Database Environment HardwareHardware Software: DBMS, application program and query softwareSoftware: DBMS, application program and query software Data: Organized in a schema, partitioned into subschemasData: Organized in a schema, partitioned into subschemas Procedures: Govern the design, access and use of the databaseProcedures: Govern the design, access and use of the database People: Administrators (DA, DBA), designers (logical and physical), application developers and users (novice and high-powered)People: Administrators (DA, DBA), designers (logical and physical), application developers and users (novice and high-powered)

18 R. Ching, Ph.D. MIS Dept. California State University, Sacramento Advantages of the Database Approach Control of data redundancyControl of data redundancy Data consistencyData consistency Greater informational gain, more information from the same amount of dataGreater informational gain, more information from the same amount of data Sharing data, organizational resource (i.e., shared resource)Sharing data, organizational resource (i.e., shared resource) Improved data integrity, validity and consistencyImproved data integrity, validity and consistency Improved access and securityImproved access and security Enforcement of standardsEnforcement of standards

19 R. Ching, Ph.D. MIS Dept. California State University, Sacramento Advantages of the Database Approach Economy of scale, centralization and consolidationEconomy of scale, centralization and consolidation Balancing of conflicting requirements, DBA oversees data and data definitionsBalancing of conflicting requirements, DBA oversees data and data definitions Improved data accessibility and responsivenessImproved data accessibility and responsiveness Increased productivityIncreased productivity Improved maintenance through data independenceImproved maintenance through data independence Increased currencyIncreased currency Improved backup and recovery servicesImproved backup and recovery services

20 R. Ching, Ph.D. MIS Dept. California State University, Sacramento Disadvantages of the Database Approach ComplexityComplexity SizeSize Cost of DBMSCost of DBMS Additional hardware costsAdditional hardware costs Cost of conversionCost of conversion PerformancePerformance Higher impact of failureHigher impact of failure In a production environment, processing can be slowIn a production environment, processing can be slow Dedication of resources including technology and people infrastructures