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7/30/2019 DSI 05 Database
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Principles of Information Systems
Eighth Edition
Organizing Data and
Information
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Principles of Information Systems, Eighth Edition 2
Learning Objectives
– Define general data management concepts and
terms, highlighting the advantages of the database
approach to data management
– Describe the relational database model and outlineits basic features
– Identify the common functions performed by all
database management systems and identify popular
user database management systems
– Identify and briefly discuss current database
applications
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Principles of Information Systems, Eighth Edition 3
Why Learn About Database Systems?
• Database systems process and organize large
amounts of data
• Examples:
– Marketing manager can access customer data
– Corporate lawyer can access past cases and
opinions
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Principles of Information Systems, Eighth Edition 4
Introduction
• Database: an organized collection of data
• Database management system (DBMS): group of
programs to manage database
– Manipulates database
– Provides an interface between database and the
user of the database and other application programs
• Database administrator (DBA): skilled IS
professional who directs all activities related to anorganization’s database
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Principles of Information Systems, Eighth Edition 5
Data Management
• Without data and the ability to process it, an
organization could not successfully complete most
business activities
• Data consists of raw facts• To transform data into useful information, it must
first be organized in a meaningful way
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Principles of Information Systems, Eighth Edition 6
The Hierarchy of Data
• Bit (a binary digit): represents a circuit that is
either on or off
• Byte: typically made up of eight bits
• Character: a byte represents a character; thebasic building block of information
– Can be an uppercase letter, lowercase letter,
numeric digit, or special symbol
• Field: typically a name, number, or combination of
characters that describes an aspect of a business
object or activity
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Principles of Information Systems, Eighth Edition 7
The Hierarchy of Data (continued)
• Record: collection of related data fields
• File: collection of related records
• Database: collection of integrated and related files
• Hierarchy of data
– Bits, characters, fields, records, files, and databases
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Principles of Information Systems, Eighth Edition 8
The Hierarchy of Data (continued)
Figure 5.1: The Hierarchy of Data
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Principles of Information Systems, Eighth Edition 9
Data Entities, Attributes, and Keys
• Entity: generalized class of people, places, or
things (objects) for which data is collected, stored,
and maintained
• Attribute: characteristic of an entity• Data item: specific value of an attribute
• Key: field or set of fields in a record that is used to
identify the record
• Primary key: field or set of fields that uniquely
identifies the record
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Principles of Information Systems, Eighth Edition 10
Data Entities, Attributes, and Keys
(continued)
Figure 5.2: Keys and Attributes
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Principles of Information Systems, Eighth Edition 11
The Database Approach
• Traditional approach to data management:
separate data files are created and stored for each
application program
• Database approach to data management: a pool
of related data is shared by multiple application
programs
– Offers significant advantages over the traditional file-
based approach
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Principles of Information Systems, Eighth Edition 12
The Database Approach (continued)
Figure 5.3: The Database Approach to Data Management
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Principles of Information Systems, Eighth Edition 13
The Database Approach (continued)
Table 5.1: Advantages of the Database Approach
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Principles of Information Systems, Eighth Edition 14
The Database Approach (continued)
Table 5.1: Advantages of the Database Approach (continued)
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Principles of Information Systems, Eighth Edition 15
The Database Approach (continued)
Table 5.2: Disadvantages of the Database Approach
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Principles of Information Systems, Eighth Edition 16
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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Principles of Information Systems, Eighth Edition 17
Data Modeling
• Building a database requires two types of designs
– Logical design: abstract model of how the data
should be structured and arranged to meet an
organization’s information needs – Physical design: starts from the logical database
design and fine-tunes it for performance and cost
considerations
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Principles of Information Systems, Eighth Edition 18
Data Modeling (continued)
• Data model: diagram of data entities and their
relationships
• Entity-relationship (ER) diagrams: data models
that use basic graphical symbols to show theorganization of and relationships between data
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Principles of Information Systems, Eighth Edition 19
Data Modeling (continued)
Figure 5.4: An Entity-Relationship (ER) Diagram for a Customer Order
Database
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Principles of Information Systems, Eighth Edition 20
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 – Each row of a table represents a data entity
– Columns of the table represent attributes
– Domain: allowable values for data attributes
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Principles of Information Systems, Eighth Edition 21
The Relational Database Model
(continued)
Figure 5.5: A Relational Database Model
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Principles of Information Systems, Eighth Edition 22
The Relational Database Model
(continued)
• Selecting: eliminates rows according to certain
criteria
• Projecting: eliminates columns in a table
• Joining: combines two or more tables• Linking: manipulating two or more tables that
share at least one common data attribute to
provide useful information and reports
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Principles of Information Systems, Eighth Edition 23
The Relational Database Model
(continued)
Figure 5.6: A Simplified ER Diagram Showing the Relationship Between
the Manager, Department, and Project Tables
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Principles of Information Systems, Eighth Edition 24
The Relational Database Model
(continued)
Figure 5.7: Linking Data Tables to Answer an Inquiry
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Principles of Information Systems, Eighth Edition 25
The Relational Database Model
(continued)
• Data cleanup: process of looking for and fixinginconsistencies to ensure that data is accurate andcomplete
– Eliminate redundancies and anomalies
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Principles of Information Systems, Eighth Edition 26
The Relational Database Model
(continued)
Table 5.3: Fitness Center Dues
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Principles of Information Systems, Eighth Edition 27
The Relational Database Model
(continued)
Table 5.5: Dues Paid
Table 5.4: Fitness Center Members
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Principles of Information Systems, Eighth Edition 28
Database Management Systems
(DBMSs)
• Creating and implementing the right database
system ensures that the database will support both
business activities and goals
• DBMS: a group of programs used as an interface
between a database and application programs or a
database and the user
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Principles of Information Systems, Eighth Edition 29
Overview of Database Types
• Flat file
– Simple database program whose records have no
relationship to one another
• Single user – Only one person can use the database at a time
– Examples: Access, FileMaker, and InfoPath
• Multiple user
– Allows dozens or hundreds of people to access the
same database system at the same time
– Examples: Oracle, Sybase, and IBM
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Principles of Information Systems, Eighth Edition 30
Providing a User View
• Schema: description of the entire database
– Typically used by large database systems to define
tables and other database features associated with a
person or user • A DBMS can reference a schema to find where to
access the requested data in relation to another
piece of data
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Principles of Information Systems, Eighth Edition 31
Creating and Modifying the Database
• Data definition language (DDL): collection of
instructions and commands used to define and
describe data and relationships in a specific
database – Allows the database’s creator to describe the data
and relationships that are to be contained in the
schema
• Data dictionary: detailed description of all the dataused in the database
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Principles of Information Systems, Eighth Edition 32
Creating and Modifying the Database
(continued)
Figure 5.10: Using a Data Definition Language to Define a Schema
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Principles of Information Systems, Eighth Edition 33
Creating and Modifying the Database
(continued)
Figure 5.11: A Typical Data Dictionary Entry
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Principles of Information Systems, Eighth Edition 34
Storing and Retrieving Data
• When an application program requests data from
the DBMS, the application program follows a
logical access path
• When the DBMS goes to a storage device toretrieve the requested data, it follows a path to the
physical location (physical access path) where the
data is stored
• Concurrency control?
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Principles of Information Systems, Eighth Edition 35
Storing and Retrieving Data
(continued)
Figure 5.12: Logical and Physical Access Paths
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Principles of Information Systems, Eighth Edition 36
Manipulating Data and Generating
Reports
• Data manipulation language (DML): commands
that manipulate the data in a database
• Structured Query Language (SQL)
– Adopted by the American National StandardsInstitute (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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Principles of Information Systems, Eighth Edition 37
Manipulating Data and Generating
Reports (continued)
Table 5.6: Examples of SQL Commands
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Principles of Information Systems, Eighth Edition 38
Database Administration
• Role of the database administrator (DBA): plan,
design, create, operate, secure, monitor, and
maintain databases
• DBA works with both users and programmers• A data administrator is responsible for defining and
implementing consistent principles for a variety of
data issues, including setting data standards and
data definitions; a nontechnical position
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Principles of Information Systems, Eighth Edition 39
Popular Database Management
Systems
• Popular DBMSs for end users include Microsoft’s Access and FileMaker Pro
• Complete database management software marketincludes:
– Software for professional programmers
– Databases for midrange, mainframe, andsupercomputers
• 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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Principles of Information Systems, Eighth Edition 40
Special-Purpose Database Systems
• Some specialized database packages are used for
specific purposes or in specific industries
– Israeli Holocaust Database (www.yadvashem.org )
– Hazmat database – Art and Antique Organizer Deluxe
• Special-purpose database by Tableau can be used
to store and process visual images
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Principles of Information Systems, Eighth Edition 41
Selecting a Database Management
System
• Important characteristics of databases to consider
– Database size
– Database cost
– Concurrent users – Performance
– Integration
– Vendor
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Principles of Information Systems, Eighth Edition 42
Using Databases with Other Software
• DBMSs can act as front-end or back-end
applications
– Front-end applications interact directly with people or
users – Back-end applications interact with other programs
or applications
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Principles of Information Systems, Eighth Edition 43
Database Applications
• Today’s database applications manipulate the
content of a database to produce useful information
• Common manipulations are searching, filtering,
synthesizing, and assimilating the data contained ina database using a number of database
applications
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Principles of Information Systems, Eighth Edition 44
Linking Databases to the Internet
• Linking databases to the Internet is important for
many organizations and people
• Semantic Web
– Developing a seamless integration of traditionaldatabases with the Internet
– Allows people to access and manipulate a number of
traditional databases at the same time through the
Internet
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Principles of Information Systems, Eighth Edition 45
Data Warehouses, Data Marts, and
Data Mining
• Data warehouse: database that collects business
information from many sources in the enterprise,
covering all aspects of the company’s processes,
products, and customers• Data mart: subset of a data warehouse
• Data mining: information-analysis tool that
involves the automated discovery of patterns and
relationships in a data warehouse
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Principles of Information Systems, Eighth Edition 46
Data Warehouses, Data Marts, and
Data Mining (continued)
Figure 5.17: Elements of a Data Warehouse
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Principles of Information Systems, Eighth Edition 47
Data Warehouses, Data Marts, and
Data Mining (continued)
Table 5.8: Common Data-Mining Applications
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Principles of Information Systems, Eighth Edition 48
Distributed Databases
• Distributed database
– Database in which the data may be spread across
several smaller databases connected via
telecommunications devices
– Gives corporations more flexibility in how databases
are organized and used
• Replicated database
– Database that holds a duplicate set of frequentlyused data
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Principles of Information Systems, Eighth Edition 49
Object-Oriented and Object-Relational
Database Management Systems
• Object-oriented database: database that stores
both data and its processing instructions
– Method: procedure or action
– Message: request to execute or run a method
Object Oriented and Object Relational
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Principles of Information Systems, Eighth Edition 50
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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Principles of Information Systems, Eighth Edition 51
Visual, Audio, and Other Database
Systems
• Databases for storing images
• Databases for storing sound
• Virtual database systems: allow different
databases to work together as a unified databasesystem
• Other special-purpose database systems
– Spatial data technology: stores and accesses data
according to the locations it describes and permitsspatial queries and analysis
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Principles of Information Systems, Eighth Edition 52
Summary
• Database: a collection of integrated and related files
• Hierarchy of data: bits, characters, fields, records,
files, and databases
• Key: a field or set of fields in a record that is used toidentify the record
• Database approach to data management: a pool of
related data is shared by multiple application
programs• Data model: diagram of entities and relationships
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Principles of Information Systems, Eighth Edition 53
Summary (continued)
• Relational model: describes data in which all
elements are placed in two-dimensional tables
called relations
• Database management system (DBMS): group of programs used as an interface between a database
and application programs or a database and the
user
• Role of the database administrator (DBA): plan,design, create, operate, secure, monitor, and
maintain databases
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Summary (continued)
• Data warehouse: database that collects business
information from all aspects of a company’s
processes, products, and customers
• Data mining: information-analysis tool for theautomated discovery of patterns and relationships
in a data warehouse
• Object-oriented database: database that stores
both data and its processing instructions