© 2007 by Prentice Hall
© 2007 by Prentice Hall Management Information Systems, 10/e RManagement Information Systems, 10/e R
aymond McLeod and George Schell
aymond McLeod and George Schell
1
1
Management
Management
Information Systems,
Information Systems,
10/e
10/e
Raymond McLeod and George
Raymond McLeod and George
Schell
Chapter 6
Chapter 6
Database Management
Database Management
Systems
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
3
Learning Objectives
Learning Objectives
►
Understand the hierarchy of data.
Understand the hierarchy of data.
►
Understand database structures and how they
Understand database structures and how they
work.
work.
►
Know how to relate tables together in a
Know how to relate tables together in a
database.
database.
►
Recognize the difference between a database
Recognize the difference between a database
and a database management system.
and a database management system.
►
Understand the database concept.
Understand the database concept.
►
Know two basic methods for determining data
Know two basic methods for determining data
needs.
Learning Objectives (Cont’d)
Learning Objectives (Cont’d)
►
Understand entity-relationship diagrams and
Understand entity-relationship diagrams and
class diagrams.
class diagrams.
►
Know the basics of reports and forms.
Know the basics of reports and forms.
►
Understand the basic difference between
Understand the basic difference between
structured query language and
structured query language and
query-by-example.
example.
►
Know about the important personnel who are
Know about the important personnel who are
associated with databases.
associated with databases.
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
5
Data Hierarchy
Data Hierarchy
►
Data field
Data field
is the smallest unit of data.
is the smallest unit of data.
►
Record
Record
is a collection of related data
is a collection of related data
fields.
fields.
►
File
File
is a collection of related records.
is a collection of related records.
►
Database
Database
is a collection of related
is a collection of related
files.
files.
General definition
General definition
Database
Database
►
Table of rows & columns can be represented in a
Table of rows & columns can be represented in a
spreadsheet.
spreadsheet.
►
Relational database structure
Relational database structure
is conceptually
is conceptually
similar to a collection of related tables.
similar to a collection of related tables.
►
Flat file
Flat file
is a table that does not have repeating
is a table that does not have repeating
columns; 1
columns; 1
ststnormal form.
normal form.
►
Normalization
Normalization
is a formal process for
is a formal process for
eliminating redundant data fields which
eliminating redundant data fields which
preserving the ability of the database to add,
preserving the ability of the database to add,
delete, and modify records without causing
delete, and modify records without causing
errors.
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
7
Figure 6.1 Spreadsheet as a
Figure 6.1 Spreadsheet as a
Database (Cont’d)
Database (Cont’d)
►
Key
Key
in a table is a field (or combination of
in a table is a field (or combination of
fields) that contain a value that uniquely
fields) that contain a value that uniquely
identifies each record in the table.
identifies each record in the table.
►
Candidate key
Candidate key
is a field that uniquely
is a field that uniquely
identifies each table row but is not the
identifies each table row but is not the
chosen key.
chosen key.
►
Relating tables is done through sharing a
Relating tables is done through sharing a
common field & the value of the field
common field & the value of the field
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
9
Database Management
Database Management
System
System
►
Database management system
Database management system
(DBMS)
(DBMS)
is a software application that
is a software application that
stores the structure of the database,
stores the structure of the database,
the data itself, relationships among
the data itself, relationships among
data in the database, and forms &
data in the database, and forms &
reports pertaining to the database.
Database Structures
Database Structures
►
Hierarchical
Hierarchical
is formed by data
is formed by data
groups, subgroups, and further
groups, subgroups, and further
subgroups; like branches on a tree.
subgroups; like branches on a tree.
Worked well with TPSs.
Worked well with TPSs.
Utilized computer resources efficiently.
Utilized computer resources efficiently.
►
Network
Network
allows retrieval of specific
allows retrieval of specific
records; allows a given record to point
records; allows a given record to point
to any other record in the database.
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
[image:11.720.41.684.151.523.2]11
Figure 6.2 Hierarchical
Figure 6.2 Hierarchical
Database Structures (Cont’d)
Database Structures (Cont’d)
►
Relational
Relational
is when the relationship
is when the relationship
between tables are implicit.
between tables are implicit.
►
Physical relationship
Physical relationship
is when the
is when the
database structure (hierarchical,
database structure (hierarchical,
network) rely on storage addresses.
network) rely on storage addresses.
►
Implicit relationship
Implicit relationship
is when the
is when the
database structure (relational) can be
database structure (relational) can be
implied from the data.
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
13
A Relational Database
A Relational Database
Example
Example
►
A database named
A database named
Schedule
Schedule
has been created
has been created
from tables used earlier in the chapter and some
from tables used earlier in the chapter and some
others
others
►
The database is implemented in Microsoft
The database is implemented in Microsoft
Access 2002 (also known as Access XP).
Access 2002 (also known as Access XP).
►
Databases break information into multiple tables
Databases break information into multiple tables
because if information were stored in a single
because if information were stored in a single
table, many data field values would be
table, many data field values would be
duplicated.
Schedule
Schedule
Database
Database
►
The example is implemented on Microsoft Access DBMS but
The example is implemented on Microsoft Access DBMS but
would be similar on any relational DBMS product.
would be similar on any relational DBMS product.
►
The COURSE table in Access (Figure 6.4) is a list of data field
The COURSE table in Access (Figure 6.4) is a list of data field
values. The table itself had to be defined in Access before values
values. The table itself had to be defined in Access before values
were entered into the data fields.
were entered into the data fields.
►
Figure 6.5 shows the definition of the
Figure 6.5 shows the definition of the
Code
Code
field.
field.
►
Figure 6.6 illustrates that
Figure 6.6 illustrates that
Abbreviation
Abbreviation
field values will be
field values will be
looked up from a list of values in the DEPARTMENT table.
looked up from a list of values in the DEPARTMENT table.
►Table 6.7 shows a single table of course and department fields
Table 6.7 shows a single table of course and department fields
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
15
Figure 6.5 Defining the CODE
Figure 6.5 Defining the CODE
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
[image:17.720.54.685.145.526.2]17
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
[image:19.720.58.683.220.529.2]19
Database Concept
Database Concept
►
Database concept
Database concept
is the logical integration
is the logical integration
of records across multiple physical locations.
of records across multiple physical locations.
►
Data independence
Data independence
is the ability to make
is the ability to make
changes in the data structure without making
changes in the data structure without making
changes to the application programs that
changes to the application programs that
access the data.
access the data.
►
Data dictionary
Data dictionary
includes the definition of
includes the definition of
the data stored within the database &
the data stored within the database &
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
21
Creating a Database
Creating a Database
►
Determine data that needs to be
Determine data that needs to be
collected & stored is a key step.
collected & stored is a key step.
►
Process-oriented approach
Process-oriented approach
Define the problem.
Define the problem.
Identify necessary decisions.
Identify necessary decisions.
Describe information needs.
Describe information needs.
Determine Data Needs
Determine Data Needs
(Cont’d)
(Cont’d)
►
Enterprise modeling approach
Enterprise modeling approach
takes a broad view of the firm’s data
takes a broad view of the firm’s data
resources; all areas are considered, &
resources; all areas are considered, &
synergy of data resources between
synergy of data resources between
business areas can be leveraged.
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
23
Figure 6.8 Enterprise Data
Figure 6.8 Enterprise Data
Data Modeling Techniques
Data Modeling Techniques
►
Entity-relationship diagrams (ERDs)
Entity-relationship diagrams (ERDs)
is a graphical representation of data in
is a graphical representation of data in
entities and the relationships between
entities and the relationships between
entities.
entities.
►
Entity
Entity
is a conceptual collection of
is a conceptual collection of
related data fields.
related data fields.
►
Relationship
Relationship
is defined between entities.
is defined between entities.
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
[image:25.720.27.678.145.525.2]25
Figure 6.11 Entity-relationship
Figure 6.11 Entity-relationship
Diagramming Techniques
Diagramming Techniques
(Cont’d)
(Cont’d)
►
Class Diagram
Class Diagram
is a graphical
is a graphical
representation of both the data used in
representation of both the data used in
an application and the actions associated
an application and the actions associated
with the data; object-oriented design
with the data; object-oriented design
model
model
►
Objects
Objects
are the data, actions taken on
are the data, actions taken on
the data, & relationship between objects.
the data, & relationship between objects.
►
Class diagrams consist of the named
Class diagrams consist of the named
class, fields in the class, & actions
class, fields in the class, & actions
(
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
[image:27.720.58.704.113.530.2]27
Using the Database
Using the Database
►
Forms
Forms
show 1 record at a time & can
show 1 record at a time & can
be used to add, delete, or modify
be used to add, delete, or modify
database records.
database records.
Navigation
Navigation
Accuracy
Accuracy
Consistency
Consistency
Filtering
Filtering
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
29
Figure 6.15 Combined Data
Figure 6.15 Combined Data
Using the Database (Cont’d)
Using the Database (Cont’d)
►
Reports
Reports
are aggregated data from the
are aggregated data from the
database that are formatted in a manner
database that are formatted in a manner
that aids decision making.
that aids decision making.
►
Queries
Queries
is a request for the database to
is a request for the database to
display selected records.
display selected records.
►
Query-by-example (QBE)
Query-by-example (QBE)
presents a
presents a
standardized form that the user
standardized form that the user
completes so the system can generate a
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
[image:31.720.0.696.190.531.2]31
Figure 6.16 Report of
Figure 6.16 Report of
Structured Query Language
Structured Query Language
►
Structured query language (SQL)
Structured query language (SQL)
is the code that RDBMSs use to
is the code that RDBMSs use to
perform their database tasks.
perform their database tasks.
►
Method of choice for interacting with
Method of choice for interacting with
web-based databases.
web-based databases.
►
Writing SQL statements are not
Writing SQL statements are not
difficult for most manager’s data
difficult for most manager’s data
needs.
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
33
Advanced Database
Advanced Database
Processing
Processing
►
On-line analytical processing (OLAP)
On-line analytical processing (OLAP)
allows data analysis similar to statistical
allows data analysis similar to statistical
cross-tabulation.
cross-tabulation.
►
Data mining
Data mining
,
,
data marts
data marts
, &
, &
data
data
warehousing
warehousing
focus on methodologies that
focus on methodologies that
offer users quick access to aggregated data
offer users quick access to aggregated data
specific to their decision-making needs.
specific to their decision-making needs.
►
Knowledge discovery
Knowledge discovery
analyzes data usage
analyzes data usage
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
35
Database Personnel
Database Personnel
►
Database Administrator (DBA)
Database Administrator (DBA)
is
is
an expert in developing, providing, and
an expert in developing, providing, and
securing databases; duties include
securing databases; duties include
Database planning;
Database planning;
Database implementation;
Database implementation;
Database operation;
Database operation;
Database Personnel (Cont’d)
Database Personnel (Cont’d)
►
Database programmer
Database programmer
writes code
writes code
to strip and/or aggregate data from
to strip and/or aggregate data from
the database
the database
High level of specialization & selection
High level of specialization & selection
►
End user
End user
generates reports & forms,
generates reports & forms,
post queries to the database, & use
post queries to the database, & use
results from their database inquiries to
results from their database inquiries to
make decisions that affect the firm &
make decisions that affect the firm &
its environmental constituents.
© 2007 by Prentice H all
Management Information S ystems, 10/e Raymond Mc Leod and George Schell
37
DBMSs in Perspective
DBMSs in Perspective
►
DBMS Advantages
DBMS Advantages
Reduce data redundancy.
Reduce data redundancy.
Achieve data independence.
Achieve data independence.
Retrieve data & information rapidly.
Retrieve data & information rapidly.
Improve security.
Improve security.
►
DBMS Disadvantages
DBMS Disadvantages
Obtain expensive software.
Obtain expensive software.
