A Data Mining Application in a Student Database

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					Database Management


     An Introduction
Goals For Today:
 Describe why databases have become so
  important to modern organizations
 Describe what database and database
  management systems are and how they work.
 Explain four emerging database trends:
    –   (1) client / server computing,
    –   (2) object-oriented databases,
    –   (3) data mining, and
    –   (4) integrating Web applications
Database Defined
   Database:
    –   A collection of related data organized in a way
        that facilitates data searches.
   What are some examples of Databases?
Example of a Student Database
 Types of Data Collected in a Typical Student Database
              Databases
     Before the Use of Computers
   Data was stored in:
    –   books
    –   ledgers
    –   card files
    –   folders
    –   file cabinets
    –   or simply in people’s heads!?
Computers make the process of
storing and managing data easier
The Database Approach
   Database Management System
    –   software application which allows you to
        create, store, organize, and retrieve data from a
        single database or many databases.
    –   Example: MS Access
   Entity
    –   something you collect data about
    –   Examples: people or classes
A Database Contains
the Following:
   Tables
    –   how entities are represented in a database,
        where each row is a record and each column a
        field.
   Fields
    –   individual pieces of information
   Record
    –   collection of related fields within one entity
Sample Data Table
(page 2-94 in your book)
Key Database Issues
and Activities
 Entering and Querying Data
 Creating Database Reports
 Data Structure
 Data Type
Entering Data
   Data Entry:
    –   process of getting information into a database
    –   possible methods of data entry:
              Entry Professional, Electronic Files, Historical
          Data
          Records, or Web Based (Forms)
Querying Data
   Querying:
    –   how we get information from a database
   Structured Query Language (SQL):
    –   most common language used to interface with
        databases
    –   Example:
         SELECT DISTINCTROW STUDENT_ID, GRADE
         FROM GRADES
         WHERE GRADE = “A”
         ORDER BY STUDENT_ID;
Querying Data continued
   Query By Example (QBE)
    –   enables you to fill out a grid, or template, in
        order to construct a description of the data you
        would like to retrieve.
Creating Database Reports
   Report:
    –   A compilation of data from the database that is
        organized and produced in a printed format.
    –   Typically produced on paper, but also can be
        displayed on-screen.
    –   Example: Quarterly Sales Report
Data Structure
   Database has two parts:
    –   Data
    –   Data Structure: how the data is organized.
   Data Model:
    –   representation of entities and their relationships
        to the real world
   Primary Key:
    –   a unique identifier in the database
    –   one or more fields
Data Structure continued

                Primary Key is Student ID
Data Type
   Data Type:
    –   each field in the database needs to be of a
        certain type
    –   Examples: text, number, dates
   Data Dictionary:
    –   a document (often published online) prepared
        by the database designers to aid users in data
        entry.
Data Dictionary Example:

                   Students Table

Primary Key   Field Name   Field Type   Field Length
yes           Student ID   Number        9
no            Last Name    Text          20
no            First Name   Text          15
Database Management
Systems Approaches
 The Hierarchical Model
 The Network Model
 Relational Model
 Normalization
 Associations
The Hierarchical Model

   Records in parent entities can have many
    child records, but each child can have only
    one parent.
                                          Parent


                                          Child
The Network Model

   In this case you can have multiple children
    and parents       Parents




                                          Children
The Relational Model
 –   A good relational database design eliminates
     unnecessary data duplications and is, therefore,
     easier to maintain
 –   Relationship: joining two tables on a common
     field


                                           Relationship
Normalization
 A technique used to make complex databases
  more efficient and easier to handle
 Eliminates Redundant Data
Normalization continued
Database w/redundant data
Database after
Normalization
Three Types of
Associations or Relationships
 –   One-to-One
         Each team has only one home stadium, and each home stadium
          has only one team
            – Team ID Team Name Location Stadium ID

 –   One-to-Many
         Each Player is on only one team, but each team has many
          players
            – Player ID Player Name Position        Team ID
 –   Many-to-Many
         Each player participates in many games, and each game has
          many players
            Team 1 Team 2 Date Player ID Points Minutes Fouls
Recent Developments Affecting
Database Design and Use
 Databases and Client / Server Computing
 Object-Oriented Databases
 Data Mining
 Linking Web Site Applications to
  Organizational Databases
Databases and Client / Server
Computing
   Database application is divided into two parts:
    –   Database Server
          where   all data is stored on a powerful machine
    –   PC Client
          theprogram used to manipulate the data resides on an
          individual user’s computer
Object-Oriented Databases
 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).
 Most of today’s database applications have
  some of these Object characteristics.
Data Mining
 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.
 Example: Grocery Store Club Cards
Data Mining continued
   Data Warehouses
    –   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
Data Warehouse Examples
TELECOMMUNICATIONS                   REPRESENTATIVE COMPANIES
Analysis of the following:               AT&T
  Call volumes                           Ameritech
  Equipment sales                        Belgacom
  Customer profitability                 British Telecom
  Costs                                  Telestra AustraliaTelecom Ireland
  Inventory                              Telecom Italia
Purchasing leverage with suppliers
Frequent buyer program management
Data Mining continued
   Data Marts
    –   A small-scale data warehouse that contains a
        subset of the data for a single aspect of a
        company’s business
    –   Examples: finance, inventory, or personnel
Linking Web Site Applications to
Organizational Databases
   Example:
    –   many comapies are enabling users of their Web
        Site to:
           view product catalogs,
          check inventory, and
          place orders

        these are all actions that read and write to the
        organizations’ databases.
Goals For Today:
 Described why databases have become so
  important to modern organizations
 Described what database and database
  management systems are and how they work.
 Explained four emerging database trends:
    –   (1) client / server computing,
    –   (2) object-oriented databases,
    –   (3) data mining, and
    –   (4) integrating Web applications

				
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