Download Functions of A Database Management System

Chapter 4
Database
Management
Systems
What is a Database
Management System (DBMS)?
 Database
• An organized collection of related data
 Database Management System
• Comprises programs to store, retrieve, and
otherwise manage a computerized
database and to provide interfaces to
application programs and to nonprogramming users
Chapter 4
Slide 2
Functions of A Database Management
System
 Storing and Retrieving Data
• The database sees the physical view of
the data
How the data are compressed and formatted,
which data are stored near each other, and
which indexes are created to simplify and
speed finding data on the storage medium
Chapter 4
Slide 3
FunctionsofofAADatabase
Database Management
Functions
Management System
System
 Storing and Retrieving Data
• The database presents a logical view to
the user and programmer
Organizes and presents data elements in ways
that managers and other users find helpful
Chapter 4
Slide 4
FunctionsofofAADatabase
Database Management
Functions
Management System
System
 Managing Metadata
• Metadata are data about data in the
database
• Example
The fact that a company's invoice numbers are
six digits long, with the first digit being either a
1 or 3
Chapter 4
Slide 5
FunctionsofofAADatabase
Database Management
Functions
Management System
System
 Limiting and Controlling Redundant
Data in Multiple Systems
• Companies often collect and store the
same data in two or more different
information systems
Chapter 4
Slide 6
FunctionsofofAADatabase
Database Management
Functions
Management System
System
 Supporting Simultaneous Data
Sharing
• Concurrency control
Describes the proper management of
simultaneous attempts to update a database by
multiple users or multiple software programs
Chapter 4
Slide 7
FunctionsofofAADatabase
Database Management
Functions
Management System
System
 Providing Transaction Atomicity
• The concept that a transaction cannot be
split into smaller parts
• If systems fails in midst of transaction,
system is restored as if the entire
transaction completed or no part of it
completed
Chapter 4
Slide 8
FunctionsofofAADatabase
Database Management
Functions
Management System
System
 Providing Backup and Recovery
Services
• Databases cannot be backed up like files
because they are too large and in constant
use
• Backup techniques include
Operating in parallel on two storage devices
Use of temporary database during backup
Chapter 4
Slide 9
Functions of A Database Management
System
 Providing Authorization and Security
Services
• Most DBMSs can limit who has access to
specific data
• DBMS can create limited views of data so
that users can see only what they are
authorized to see
Chapter 4
Slide 10
Functions of A Database Management
System
 Enforcing Business Rules
• A DBMS enforces rules that ensure related
data are logically consistent
Chapter 4
Slide 11
Database Applications
 Support for Application Software
• Providing a common data repository
• Performing support functions, such as data
storage, metadata storage, concurrency
control, and other DBMS functions that
would otherwise have to be performed by
the application software
Chapter 4
Slide 12
Database Applications
 Data Warehouse
• An enterprise-wide database designed to
support business intelligence and
management decision making rather than
operational needs
Chapter 4
Slide 13
Database Applications
 Data Mart
• Provides summary and historical data for
business intelligence and decision making
for a single department or division rather
than an entire organization
Chapter 4
Slide 14
Database Applications
 Serving Dynamic Web Pages
• Allows Web content managers to change
Web pages by updating a database
• Content management
Software designed to ease the development of
Web pages by fields from a database into a
Web page template
Chapter 4
Slide 15
Developing Databases through Data
Design
 Data Design
• The process of identifying and formalizing
the relationships among the elements of
data that will form an organization's
database
Chapter 4
Slide 16
Developing Databases through Data
Design
[Insert Figure 4-4 here]
Chapter 4
Slide 17
Developing Databases through Data
Design
 Entity-Relationship (E/R) Model
• The E/R model offers a pictorial way of
showing the interrelationships among
various types of data
Chapter 4
Slide 18
The EntityRelationship Model
Figure 4-5
Chapter 4
Slide 19
Technological Underpinnings
 Distribution Architecture
• Refers to how the organization distributes
data and database processing physically
among the computers in a network
Chapter 4
Slide 20
Technological Underpinnings
 Types of Distribution Architectures
• Decentralized architecture
Involves no data sharing
• Centralized architecture
Has a single DBMS running on a single
computer and maintaining data centrally
Chapter 4
Slide 21
Technological Underpinnings
 Types of Distribution Architectures
• Client/Server architecture
Divides the functions of a DBMS among
connected computers on a network, while
centralizing permanent storage for all data on a
computer called the database server
Chapter 4
Slide 22
Technological Underpinnings
 Types of Distribution Architectures
• Distributed architecture
Distributes both data and processing
Treats data as a single database, giving every
database client and every server access to all
the data in the database no matter where it
resides
• Mixed architecture
Utilizes more than one architecture
Chapter 4
Slide 23
Technological Underpinnings
 Database Models
• Relational model
A table represents a file with rows called tuples
and columns called attributes
Chapter 4
Slide 24
Technological Underpinnings
[Insert Figure 4-8 here]
Chapter 4
Slide 25
Technological Underpinnings
 Database Models
• Object model
Derives from object-oriented programming
Object-oriented DBMSs store objects and
object-class metadata
Chapter 4
Slide 26
Technological Underpinnings
 Database Models
• XML model
A language used to mark and identify
components of Web-based transaction
documents
Chapter 4
Slide 27
Technological Underpinnings
 Database Models
• Network model
Builds a tighter linkage between elements of
data
• Hierarchical model
A precursor to the network model, as a network
model with additional restrictions
Views data as organized in a logical hierarchy
Chapter 4
Slide 28
Managing the Data Resource
 Data Administrator
• Concerned with integrity of data, data
redundancy, access controls, and rules
about data relationships
 Database Administrator (DBA)
• Oversees functioning of particular DBMS
• More technical than data administrator
Chapter 4
Slide 29
End of
Chapter 4
Database
Management
Systems