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Database

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Database

  1. 1. Database Management An Introduction
  2. 2. Goals For Today: <ul><li>Describe why databases have become so important to modern organizations </li></ul><ul><li>Describe what database and database management systems are and how they work. </li></ul><ul><li>Explain four emerging database trends: </li></ul><ul><ul><li>(1) client / server computing, </li></ul></ul><ul><ul><li>(2) object-oriented databases, </li></ul></ul><ul><ul><li>(3) data mining, and </li></ul></ul><ul><ul><li>(4) integrating Web applications </li></ul></ul>
  3. 3. Database Defined <ul><li>Database: </li></ul><ul><ul><li>A collection of related data organized in a way that facilitates data searches. </li></ul></ul><ul><li>What are some examples of Databases? </li></ul>
  4. 4. Example of a Student Database Types of Data Collected in a Typical Student Database
  5. 5. Databases Before the Use of Computers <ul><li>Data was stored in: </li></ul><ul><ul><li>books </li></ul></ul><ul><ul><li>ledgers </li></ul></ul><ul><ul><li>card files </li></ul></ul><ul><ul><li>folders </li></ul></ul><ul><ul><li>file cabinets </li></ul></ul><ul><ul><li>or simply in people’s heads!? </li></ul></ul>
  6. 6. Computers make the process of storing and managing data easier
  7. 7. The Database Approach <ul><li>Database Management System </li></ul><ul><ul><li>software application which allows you to create, store, organize, and retrieve data from a single database or many databases. </li></ul></ul><ul><ul><li>Example: MS Access </li></ul></ul><ul><li>Entity </li></ul><ul><ul><li>something you collect data about </li></ul></ul><ul><ul><li>Examples: people or classes </li></ul></ul>
  8. 8. A Database Contains the Following: <ul><li>Tables </li></ul><ul><ul><li>how entities are represented in a database, where each row is a record and each column a field. </li></ul></ul><ul><li>Fields </li></ul><ul><ul><li>individual pieces of information </li></ul></ul><ul><li>Record </li></ul><ul><ul><li>collection of related fields within one entity </li></ul></ul>
  9. 9. Sample Data Table (page 2-94 in your book)
  10. 10. Key Database Issues and Activities <ul><li>Entering and Querying Data </li></ul><ul><li>Creating Database Reports </li></ul><ul><li>Data Structure </li></ul><ul><li>Data Type </li></ul>
  11. 11. Entering Data <ul><li>Data Entry: </li></ul><ul><ul><li>process of getting information into a database </li></ul></ul><ul><ul><li>possible methods of data entry: </li></ul></ul><ul><ul><ul><li>Data Entry Professional, Electronic Files, Historical Records, or Web Based (Forms) </li></ul></ul></ul>
  12. 12. Querying Data <ul><li>Querying: </li></ul><ul><ul><li>how we get information from a database </li></ul></ul><ul><li>Structured Query Language (SQL): </li></ul><ul><ul><li>most common language used to interface with databases </li></ul></ul><ul><ul><li>Example: </li></ul></ul><ul><ul><ul><li>SELECT DISTINCTROW STUDENT_ID, GRADE </li></ul></ul></ul><ul><ul><ul><li>FROM GRADES </li></ul></ul></ul><ul><ul><ul><li>WHERE GRADE = “A” </li></ul></ul></ul><ul><ul><ul><li>ORDER BY STUDENT_ID; </li></ul></ul></ul>
  13. 13. Querying Data continued <ul><li>Query By Example (QBE) </li></ul><ul><ul><li>enables you to fill out a grid, or template, in order to construct a description of the data you would like to retrieve. </li></ul></ul>
  14. 15. Creating Database Reports <ul><li>Report: </li></ul><ul><ul><li>A compilation of data from the database that is organized and produced in a printed format. </li></ul></ul><ul><ul><li>Typically produced on paper, but also can be displayed on-screen. </li></ul></ul><ul><ul><li>Example: Quarterly Sales Report </li></ul></ul>
  15. 16. Data Structure <ul><li>Database has two parts: </li></ul><ul><ul><li>Data </li></ul></ul><ul><ul><li>Data Structure: how the data is organized. </li></ul></ul><ul><li>Data Model: </li></ul><ul><ul><li>representation of entities and their relationships to the real world </li></ul></ul><ul><li>Primary Key: </li></ul><ul><ul><li>a unique identifier in the database </li></ul></ul><ul><ul><li>one or more fields </li></ul></ul>
  16. 17. Data Structure continued Primary Key is Student ID
  17. 18. Data Type <ul><li>Data Type: </li></ul><ul><ul><li>each field in the database needs to be of a certain type </li></ul></ul><ul><ul><li>Examples: text, number, dates </li></ul></ul><ul><li>Data Dictionary: </li></ul><ul><ul><li>a document (often published online) prepared by the database designers to aid users in data entry. </li></ul></ul>
  18. 19. Data Dictionary Example: <ul><li>Students Table </li></ul><ul><li>Primary Key Field Name Field Type Field Length </li></ul><ul><li>yes Student ID Number 9 </li></ul><ul><li>no Last Name Text 20 </li></ul><ul><li>no First Name Text 15 </li></ul>
  19. 20. Database Management Systems Approaches <ul><li>The Hierarchical Model </li></ul><ul><li>The Network Model </li></ul><ul><li>Relational Model </li></ul><ul><li>Normalization </li></ul><ul><li>Associations </li></ul>
  20. 21. The Hierarchical Model <ul><li>Records in parent entities can have many child records, but each child can have only one parent. </li></ul>Parent Child
  21. 22. The Network Model <ul><li>In this case you can have multiple children and parents </li></ul>Parents Children
  22. 23. The Relational Model <ul><ul><li>A good relational database design eliminates unnecessary data duplications and is, therefore, easier to maintain </li></ul></ul><ul><ul><li>Relationship: joining two tables on a common field </li></ul></ul>Relationship
  23. 24. Normalization <ul><li>A technique used to make complex databases more efficient and easier to handle </li></ul><ul><li>Eliminates Redundant Data </li></ul>
  24. 25. Normalization continued Database w/redundant data
  25. 26. Database after Normalization
  26. 27. Three Types of Associations or Relationships <ul><ul><li>One-to-One </li></ul></ul><ul><ul><ul><li>Each team has only one home stadium, and each home stadium has only one team </li></ul></ul></ul><ul><ul><ul><ul><li>Team ID Team Name Location Stadium ID </li></ul></ul></ul></ul><ul><ul><li>One-to-Many </li></ul></ul><ul><ul><ul><li>Each Player is on only one team, but each team has many players </li></ul></ul></ul><ul><ul><ul><ul><li>Player ID Player Name Position Team ID </li></ul></ul></ul></ul><ul><ul><li>Many-to-Many </li></ul></ul><ul><ul><ul><li>Each player participates in many games, and each game has many players </li></ul></ul></ul><ul><ul><ul><ul><li>Team 1 Team 2 Date Player ID Points Minutes Fouls </li></ul></ul></ul></ul>
  27. 28. Recent Developments Affecting Database Design and Use <ul><li>Databases and Client / Server Computing </li></ul><ul><li>Object-Oriented Databases </li></ul><ul><li>Data Mining </li></ul><ul><li>Linking Web Site Applications to Organizational Databases </li></ul>
  28. 29. Databases and Client / Server Computing <ul><li>Database application is divided into two parts: </li></ul><ul><ul><li>Database Server </li></ul></ul><ul><ul><ul><li>where all data is stored on a powerful machine </li></ul></ul></ul><ul><ul><li>PC Client </li></ul></ul><ul><ul><ul><li>the program used to manipulate the data resides on an individual user’s computer </li></ul></ul></ul>
  29. 30. Object-Oriented Databases <ul><li>treat tables, queries, and other components as generic reusable OBJECTS (rather than data) that can be mixed and matched and used in many applications (e.g. MS Excel and MS Access). </li></ul><ul><li>Most of today’s database applications have some of these Object characteristics. </li></ul>
  30. 31. Data Mining <ul><li>Allows companies to sort and analyze information to better understand customers, products, markets, or any other phase of their business for which data has been captured. </li></ul><ul><li>Example: Grocery Store Club Cards </li></ul>
  31. 32. Data Mining continued <ul><li>Data Warehouses </li></ul><ul><ul><li>An integration of multiple, large databases and other information sources into a single repository or access point that is suitable for direct querying, analysis, or processing </li></ul></ul>
  32. 33. Data Warehouse Examples <ul><li>TELECOMMUNICATIONS REPRESENTATIVE COMPANIES </li></ul><ul><li>Analysis of the following: AT&T </li></ul><ul><li>Call volumes Ameritech </li></ul><ul><li>Equipment sales Belgacom </li></ul><ul><li>Customer profitability British Telecom </li></ul><ul><li>Costs Telestra AustraliaTelecom Ireland </li></ul><ul><li>Inventory Telecom Italia </li></ul><ul><li>Purchasing leverage with suppliers </li></ul><ul><li>Frequent buyer program management </li></ul>
  33. 34. Data Mining continued <ul><li>Data Marts </li></ul><ul><ul><li>A small-scale data warehouse that contains a subset of the data for a single aspect of a company’s business </li></ul></ul><ul><ul><li>Examples: finance, inventory, or personnel </li></ul></ul>
  34. 35. Linking Web Site Applications to Organizational Databases <ul><li>Example: </li></ul><ul><ul><li>many comapies are enabling users of their Web Site to: </li></ul></ul><ul><ul><ul><li>view product catalogs, </li></ul></ul></ul><ul><ul><ul><li>check inventory, and </li></ul></ul></ul><ul><ul><ul><li>place orders </li></ul></ul></ul><ul><ul><li>these are all actions that read and write to the organizations’ databases. </li></ul></ul>
  35. 36. Goals For Today: <ul><li>Described why databases have become so important to modern organizations </li></ul><ul><li>Described what database and database management systems are and how they work. </li></ul><ul><li>Explained four emerging database trends: </li></ul><ul><ul><li>(1) client / server computing, </li></ul></ul><ul><ul><li>(2) object-oriented databases, </li></ul></ul><ul><ul><li>(3) data mining, and </li></ul></ul><ul><ul><li>(4) integrating Web applications </li></ul></ul>

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