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Database Management

Chapter 9. Database Management. Overview. Define Database Describe Database Hierarchy Describe Database Functions Describe Validation Techniques List Features of Relational Databases Explain How to Use Queries. Database. DBMS (Database Management System) Organized Collection of Data

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Database Management

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  1. Chapter 9 Database Management

  2. Overview • Define Database • Describe Database Hierarchy • Describe Database Functions • Describe Validation Techniques • List Features of Relational Databases • Explain How to Use Queries

  3. Database • DBMS (Database Management System) • Organized Collection of Data • For Quick Access, Retrieval, & Use • Database Software Allows You to • Create Database • Add, Change, & Delete Data • Sort & Query Database • Print Reports

  4. Data & Information • Processed Data Becomes Information • Largest Commercial Database • 2 PB — Yahoo (Oracle on Unix 2010)

  5. Data & Information • Data Integrity • Degree to Which Data is Correct • Database Contains Errors • Loses Integrity • GIGO (Garbage In, Garbage Out) • Cannot Get Good Information From Bad Data

  6. Database Hierarchy • Database Contains Tables • Table Contains Records • Record Contains Fields • Field Contains Characters

  7. Database Hierarchy • Field • Combination of One or More Characters • Smallest Unit of Data User Accesses • Characteristics • Name Uniquely Identifies Each Field • Data Type • Text • Numeric • Currency • Size

  8. Database Hierarchy • Record • Group of Related Fields • Key Field • AKA Primary Key • Uniquely Identifies Each Record

  9. Database Hierarchy • Table • Collection of Related Records • Each Record Contains Same Fields • Each Field Contains Different Data • Database • Group of Related Tables

  10. Maintaining Data • File Maintenance • Procedure That Keeps Data Current • Add Records • When You Obtain New Data • Change Records • Correct Inaccurate Data • Update Existing Data • Delete Records • Record No Longer Needed

  11. Maintaining Data • Validation • Comparing Data with Set of Rules • Reduce Data Entry Errors • Enhance Data Integrity • Types • Alpha / Numeric • Range • Completeness • Consistency

  12. Features • Data Dictionary • Lists Fields For Each Table in Database • Lists Properties For Each Field in Table

  13. Features • Form • On Screen Window • View Single Record • Area to Enter / View / Change Data

  14. Features • Report Generator • Creates Report • Without User’s Knowledge of Programming

  15. Features • Report Types • Detailed • Summary • Consolidates Data • Exception • Identifies Data Outside of Norm • Conditions Define Status Range

  16. Features • Query • Request Specific Data from Database • SQL (Structured Query Language) • Specify Data to Display, Print, or Store • QBE (Query By Example) • Retrieves Records that Match Criteria

  17. Features • Security • Only Authorized Users Can Access Data • Access Privileges • Define Activities Group of Users Can Perform • Read-only Privileges • User Can View Data, But Cannot Change It • Full-update Privileges • User Can View & Change Data

  18. Features • Backup • Copy of Entire Database • Log • Listing of Activities that Change Contents • Places Three Items In Log • Before Image • Actual Change • After Image

  19. Features • Log Example

  20. Database Models • Model • Rules & Standards Defining: • How Database Organizes Data • How Users View Data • Types • Relational • Object-oriented • Multidimensional

  21. Database Models • Relational • Stores Data in Tables • Consist of Rows (Records) & Columns (Fields) • Each Row has Primary Key • Related Tables Must Have Common Field

  22. Database Models • Relational

  23. Database Models • Object-Oriented • Stores Data in Objects • Can Contain Both Data & Actions • Advantages • Can Store More Types of Data • Can Access Data Faster • Programmers Can Reuse Objects

  24. Database Models • Object-Oriented Examples • Multimedia • Images, Audio Clips, Video Clips • CAD • Engineering, Architectural, Scientific Data • Groupware • Schedules, Calendars, Memos, Reports • Hypertext • Links to Other Documents

  25. Database Models • Object-Oriented Example

  26. Database Models • Multidimensional • Stores Data in More than Two Dimensions • Allow Users to Analyze Any View of Data • Advantages • Consolidates Data Faster than Relational

  27. Database Models • Multidimensional Examples • Data Warehouse • Comprehensive Data • Required to Analyze Data Across Enterprise • From Multiple Databases

  28. Database Models • Multidimensional Examples • Data Mining • Find Patterns & Relationships Among Data • Based on Open-ended User Queries • Click Stream • Every Action Visitors Take in Web Site

  29. Database Development • Process

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