ITD2011- Introduction to MIS

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ITD2011- Introduction to MIS
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UNIVERSITY OF JAZEERA

• Dr. Mohamed Sammouda

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Organizing Data and Information

• Chapter 2

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Principles and Learning Objectives

• Define general data management concepts and
  terms, highlighting the advantages and
  disadvantages of the database approach to data
  management.
• Name three database models and outline their
  basic features, advantages, and disadvantages.
• Identify the common functions performed by all
  database management systems and identify three
  popular end-user database management systems
• Identify and briefly discuss recent database
  applications.

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The Hierarchy of Data

• Data is generally organized in a hierarchy that
  begins with the smallest piece of data used by
  the computers (a bit) and progresses through the
  hierarchy of Database.
• Character the basic building block of
  information, consisting of uppercase or lowercase
  letters, numeric digits, or special symbols.
• Field typically a name, number, or combination
  of characters that describes an aspect of a
  business object or activity.
• Record a collection of related data fields.
• File a collection of related records.
• Entity generalized class of people, places, or
  things for which data is collected, stored, and
  maintained.
• Attribute A characteristic of an entity.
• Data item the specific value of an attribute.

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The Hierarchy of Data
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Keys and Attributes
Key a field or set of fields in a record that is
used to identify the record. Primary key a field
or set of fields that uniquely identifies the
records.
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The Traditional Approach To Data Management

• One of the most basic ways to manage data is via
  files. File is a collection of related records,
  all records associated with a particular
  application.
• Traditional approach to data management an
  approach whereby separate data files are created
  and stored for each application program.
• With traditional approach, one or more data files
  is created and used for every application.
• Data redundancy is the duplication of data in
  separate files.
• Data integrity the degree to which the data in
  any file is accurate, therefore, conflicts with
  data redundancy.

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The Traditional Approach To Data Management
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The Database Approach to Data Management

• Database approach to data management is a more
  efficient and effective means of organizing data,
  with a pool of related data shared by multiple
  application programs.
• To use the database approach to data management,
  additional software a database management system
  (DBMS) is required.
• Database management system (DBMS) is a group of
  programs that manipulate the database and provide
  an interface between the database and the user of
  the database and other application programs.

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The Database Approach to Data Management
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Advantages of the Database Approach
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Disadvantages of the Database Approach
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Data Modeling and Database Models

• A database should be designed to store all data
  relevant to the business and provide quick access
  and easy modification. Also it must reflect the
  business process of the organization.
• When building a database, careful consideration
  must be given to these questions
• Content What data should be collected and at
  what cost?
• Access What data should be provided to which
  users and when?
• Logical structure How should data be arranged so
  that it makes sense to a given user?
• Physical organization Where should data be
  physically located?

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Data Modeling and Database Models

• Building a database requires two different type
  of designs a logical design and physical design.
• Logical design involves identifying relationships
  among the different data items and grouping them
  in an orderly fashion.
• Physical design starts from logical design and
  fine-tunes it for performance and cost
  consideration (improve response time, reduced
  storage space, lower operating cost)

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Data Modeling and Database Models

• One of the tools database designers use to show
  the logical relationships among data is the data
  model.
• Data model is a diagram of data entities and
  their relationships.
• Data modeling usually involves understanding a
  specific business problem and analyzing the data
  and information needed to deliver a solution.
• Enterprise data modeling data modeling done at
  the level of the entire enterprise.
• Entity-relationship (ER) diagrams a data model
  that uses basic graphical symbols to show the
  organization of and relationships between data.

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Entity-Relationship Diagram for a Customer
Ordering Database
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Database Models

• Hierarchical (tree) a data model in which data
  is organized in a top-down, or inverted three
  structure. The hierarchical model is best suited
  to situations in which the logical relationships
  between data can be properly represented with the
  one-to-many approach. (child has only one parent)
  
• Network in this model there is an owner-member
  relationship in which a member may have many
  owners. So this model is capable of supporting
  many-to-many relationships.

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Database Models

• Relational a database model that describes data
  in which all data elements are placed in
  two-dimensional tables, called relations, that
  are the logical equivalent of files.
• The tables in relational databases organize data
  in rows and columns, simplifying data access and
  manipulation.
• In this model, each row of a table represents a
  data entity, with the columns of the table
  representing attributes. Each attributes can take
  on only one value. The allowable values for these
  attributes are called the domain.

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Hierarchical Database Model
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Network Database Model
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Relational Database Model
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Relational Models

• Once data has been placed into a relational
  database, users can make inquires and analyze
  data. Basic data manipulation include selecting,
  projecting, and joining.
• Selecting involves choosing rows according to
  certain criteria. (find the department number for
  the project 226)
• Projecting involves choosing columns in a table.
  (create new table having only department number
  and SSN)
• Joining involves combining two or more tables.
  (we can combine the project table and department
  table to get new table with the project numbers,
  project description, department name, and social
  security number for the manager in charge of the
  project)
• As long as the tables share at least one common
  data attributes, therefore these tables can be
  linked to provide a useful information and
  reports.

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Linking Database Tables to Answer an Inquiry
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Building and Modifying a Relational Database
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Database Management Systems
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Providing a User View

• DBMS is responsible for access to a database.
  Installing and using a database involves defining
  the logical and physical structure of the data
  and relationships among the data in the database.
  
• Schema - a description of the entire database
• Subschema - a file that contains a description of
  a subset of the database and identifies which
  users can modify the data items in that subset

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The Use of Schemas and Subschemas
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Creating and Modifying the Database

• Data definition language (DDL) - a collection of
  instructions and commands used to define and
  describe data and data relationships in a
  specific database
• Data dictionary detailed description of data in
  a database
• Data manipulation language (DML) commands that
  are used to manipulate the data in a database.

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Typical Uses of a Data Dictionary

• Provide a standard definition of terms and data
  elements
• Assist programmers in designing and writing
  programs
• Simplify database modification
• Reduce data redundancy
• Increase data reliability
• Speed program development
• Ease modification of data and information

Administering Databases Database administrator
(DBA) a highly skilled and trained systems
professional who directs or performs all
activities related to maintaining a successful
database environment. Data Administrator a
non-technical but important person who ensures
that data is managed as an important
organizational resource.
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Storing and Retrieving Data
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Database Features

• Tables
• Records
• Fields
• Record sorting
• Queries
• Forms
• Reports

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Creating a Database
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Creating a Query
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Structured Query Language
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Database Output
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Popular Database Management Systems

• Paradox database
• FileMaker Pro
• Microsoft Access
• Lotus 1-2-3 Spreadsheet

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Worldwide Database Market Share (2001)
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Selecting a Database Management System

• Database size depends on the number of records
  or files in the database.
• Number of concurrent users the number of
  simultaneous users that can access the contents
  of the database.
• Performance how fast the database can update
  records can be the most important criteria for
  some organization.
• Integration the ability to integrate with other
  application and database.
• Features the security procedures, privacy
  protection and a variety of tools.
• Vendor the size, reputation, and financial
  stability of the vendor should also be considered
  in making and database purchase.
• Cost database packages for personal computers
  can cost a few hundred dollars, while large
  database systems for mainframe computers can cost
  hundreds of thousand of dollars.

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Database Applications
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Data Warehouses, Data Marts, and Data Mining

• Data Warehouse - a database that collects
  business information from many sources in the
  enterprise, covering all aspects of the companys
  processes, products, and customers. data
  warehouse provides business users with a
  multidimensional view of the data they need to
  analyze business conditions.
• Data Mart a subset of a data warehouse.
  rather than store all enterprise in one
  monolithic database, data marts contain a subset
  of the data for the single aspect of a companys
  business.
• Data Mining - an information analysis tool that
  involves the automated discovery of patterns and
  relationships in a data warehouse.

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Elements of a Data Warehouse
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Common Data Mining Applications
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Object-Relational Database Management System

• A DBMS capable of manipulating the following
  types of data as objects
• audio
• images
• unstructured
• text
• spatial data

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Spatial Technology
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Summary

• Data - one of the most valuable resources a firm
  possesses.
• Entity - a generalized class of objects for which
  data is collected, stored, and maintained.
• Attribute - a characteristic of an entity.
• DBMS - a group of programs used as an interface
  between a database and application programs.
• Data mining - the automated discovery of patterns
  and relationships in a data warehouse.