The database approach to data management provides significant advantages over the traditional fileba

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• The database approach to data management provides
  significant advantages over the traditional
  file-based approach
• Define general data management concepts and
  terms, highlighting the advantages and
  disadvantages of the database approach to data
  management
• Describe the relational database model and
  outline its basic features

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• A well-designed and well-managed database is an
  extremely valuable tool in supporting decision
  making
• Identify the common functions performed by all
  database management systems and identify popular
  end-user database management systems

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• The number and types of database applications
  will continue to evolve and yield real business
  benefits
• Identify and briefly discuss current database
  applications

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Introduction

• Database management system (DBMS) group of
  programs that manipulate database and provide
  interface between database and users
• Database administrator (DBA) a skilled
  information systems professional who directs all
  activities related to organizations database

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Data Management The Hierarchy of Data

• A bit (a binary digit) represents a circuit that
  is either on or off
• A byte is typically 8 bits
• Character each byte represents a character, the
  basic building block of information
• Field typically a name, number, or combination
  of characters that describes an aspect of a
  business object or activity

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The Hierarchy of Data (continued)

• Record a collection of related data fields
• File a collection of related records
• Database a collection of integrated and related
  files
• Hierarchy of data formed by bits, characters,
  fields, records, files, and databases

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Figure 5.1 The Hierarchy of Data
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Data Entities, Attributes, and Keys

• Entity a generalized class of people, places, or
  things (objects) for which data is collected,
  stored, and maintained
• Attribute a characteristic of an entity
• Data item the specific value of an attribute
• 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 record

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Figure 5.2 Keys and Attributes
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The Traditional Approach Versus the Database
Approach

• Traditional approach separate data files are
  created and stored for each application program
• Results in data redundancy duplication of data
  in separate files
• Data redundancy conflicts with data integrity
  (the degree to which the data in any one file is
  accurate)
• Database approach approach whereby a pool of
  related data is shared by multiple application
  programs offers significant advantages over
  traditional file-based approach

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Figure 5.3 The Traditional Approach to Data
Management
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Figure 5.4 The Database Approach to Data
Management
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Table 5.1 Advantages of the Database Approach
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Table 5.1 Advantages of the Database Approach
(continued)
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Table 5.2 Disadvantages of the Database Approach
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Data Modeling and the Relational Database Model

• When building a database, an organization must
  consider
• 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

• Building a database requires two types of
  designs
• Logical design shows an abstract model of how
  the data should be structured and arranged to
  meet an organizations information needs
• Physical design starts from the logical database
  design and fine-tunes it for performance and cost
  considerations

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Data Modeling (continued)

• Data model a diagram of data entities and their
  relationships
• Entity-relationship (ER) diagrams data models
  that use basic graphical symbols to show the
  organization of and relationships between data

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Figure 5.5 An Entity-Relationship (ER) Diagram
for a Customer Order Database
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The Relational Database Model

• Relational model describes data in which all
  data elements are placed in two-dimensional
  tables, called relations, that are the logical
  equivalent of files
• In the relational model
• Each row of a table represents a data entity
• Columns of the table represent attributes
• Domain the allowable values for data attributes

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Figure 5.6 A Relational Database Model
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Manipulating Data

• Selecting eliminates rows according to certain
  criteria
• Projecting eliminates columns in a table
• Joining combines two or more tables
• Linking combines two or more tables using common
  data attributes to form a new table with only the
  unique data attributes

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Database Management Systems (DBMS)

• A group of programs used as an interface between
  a database and application programs or a database
  and user
• Database types
• Flat file
• Single user
• Multiple users

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Providing a User View

• Schema a description of the entire database
• User view the portion of the database a user can
  access
• Subschemas are used to create different user
  views
• Subschema a file that contains a description of
  a subset of the database and identifies which
  users can view and modify the data items in the
  subset

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Figure 5.10 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
• Allows the databases creator to describe the
  data and the data relationships that are to be
  contained in the schema and subschemas
• Data dictionary a detailed description of all
  the data used in the database

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Figure 5.11 Using a Data Definition Language to
Define a Schema
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Figure 5.12 A Typical Data Dictionary Entry
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Storing and Retrieving Data

• When an application program request data from
  DBMS, the application program follows a logical
  access path
• When the DBMS goes to a storage device to
  retrieve the requested data, it follows a path to
  the physical location (physical access path)
  where the data is stored

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Figure 5.13 Logical and Physical Access Paths
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Manipulating Data and Generating Reports

• Data manipulation language (DML) the commands
  that are used to manipulate the data in a
  database
• Structured Query Language (SQL) adopted by the
  American National Standards Institute (ANSI) as
  the standard query language for relational
  databases
• Once a database has been set up and loaded with
  data, it can produce reports, documents, and
  other outputs

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Table 5.6 Examples of SQL Commands
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Popular Database Management Systems

• Popular DBMSs for end users include Microsofts
  Access and Corels Paradox
• The complete database management software market
  includes databases by IBM, Oracle, and Microsoft
• Examples of open-source database systems
  PostgreSQL and MySQL
• Many traditional database programs are now
  available on open-source operating systems

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Selecting a Database Management System

• Important characteristics of databases to
  consider
• Size of the database
• Number of concurrent users
• Performance
• The ability of the DBMS to be integrated with
  other systems

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Selecting a Database Management System (continued)

• Important characteristics of databases to
  consider (continued)
• Features of the DBMS
• Vendor considerations
• Cost of the system

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Database Applications Linking the Company
Database to the Internet

• Corporate databases can be accessed by customers,
  suppliers, and company employees through
• The Internet
• Intranets
• Extranets
• Semantic Web a seamless integration of
  traditional databases with the Internet

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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 mart a subset of a data warehouse
• Data mining an information-analysis tool that
  involves the automated discovery of patterns and
  relationships in a data warehouse

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Figure 5.17 Elements of a Data Warehouse
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Table 5.8 Common Data-Mining Applications
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Business Intelligence

• Business intelligence (BI) the process of
  gathering enough of the right information in a
  timely manner and usable form and analyzing it to
  have a positive impact on business strategy,
  tactics, or operations
• Knowledge management the process of capturing a
  companys collective expertise wherever it
  resides and distributing it wherever it can help
  produce the biggest payoff

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Distributed Databases

• Distributed database
• A database in which the data may be spread across
  several smaller databases connected via
  telecommunications devices
• Corporations get more flexibility in how
  databases are organized and used
• Replicated database a database that holds a
  duplicate set of frequently used data

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Online Analytical Processing (OLAP)

• Software that allows users to explore data from a
  number of different perspectives

Table 5.9 Comparison of OLAP and Data Mining
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Open Database Connectivity (ODBC)

• Standards that ensure that software can be used
  with any ODBC-compliant database
• Can be used to export, import, or link tables
  between different applications

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Figure 5.19 Advantages of ODBC
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Object-Oriented and Object-Relational Database
Management Systems

• Object-oriented database
• Stores both data and its processing instructions
• Method a procedure or action
• Message a request to execute or run a method

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Object-Oriented and Object-Relational Database
Management Systems (continued)

• Object-oriented database management system
  (OODBMS) group of programs that manipulate an
  object-oriented database and provide a user
  interface and connections to other application
  programs
• Object-relational database management system
  (ORDBMS) DBMS capable of manipulating audio,
  video, and graphical data

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Summary

• Hierarchy of data bits, characters, fields,
  records, files, and databases
• Entity a generalized class of things (objects)
  for which data is collected, stored, and
  maintained
• Attribute characteristic of an entity
• Data model diagram of entities and relationships
• Relational model describes data in which all
  elements are placed in two-dimensional tables
  called relations

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Summary (continued)

• Selecting eliminates rows according to certain
  criteria
• Projecting eliminates columns in a table
• Database management system (DBMS) group of
  programs used as an interface
• Between a database and application programs
• Database and the user
• Data dictionary detailed description of all the
  data used in the database

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Summary (continued)

• Data warehouse database that collects business
  information from all aspects of a companys
  processes, products, and customers
• Data mining an information-analysis tool for the
  automated discovery of patterns and relationships
  in a data warehouse
• Open database connectivity (ODBC) standards
  ensure that software can be used with any
  ODBC-compliant database