1305627482_520056.pptx
Slide 1
Chapter 1 Database Systems
Slide 2
Learning Objectives
In this chapter, you will learn: The difference between data and information What a database is, the
various types of databases, and why they are valuable assets for decision making The importance
of database design How modern databases evolved from file systems
2
Slide 3
Learning Objectives
In this chapter, you will learn: About flaws in file system data management The main components of
the database system The main functions of a database management system (DBMS)
3
Slide 4
Data versus Information
Data
Information
Raw facts Have not yet been processed to reveal their meaning to the end user Building blocks of
information Data management Generation, storage, and retrieval of data
Produced by processing raw data to reveal its meaning Requires context Bedrock of knowledge
Should be accurate, relevant, and timely to enable good decision making
4
Slide 5
Introducing the Database
Shared, integrated computer structure that stores a collection of: End-user data - Raw facts of
interest to end user Metadata: Data about data, which the end-user data are integrated and
managed Describe data characteristics and relationships Database management system (DBMS)
Collection of programs Manages the database structure Controls access to data stored in the
database
5
Slide 6
Role of the DBMS
,Intermediary between the user and the database Enables data to be shared Presents the end user
with an integrated view of the data Receives and translates application requests into operations
required to fulfill the requests Hides database’s internal complexity from the application programs
and users
6
Slide 7
Figure 1.3 - The DBMS Manages the Interaction between the End User and the Database
7
Slide 8
Advantages of the DBMS
Better data integration and less data inconsistency Data inconsistency: Different versions of the
same data appear in different places Increased end-user productivity Improved: Data sharing Data
security Data access Decision making Data quality: Accuracy, validity, and timeliness of data
8
Slide 9
Types of Databases
Single-user database: Supports one user at a time Desktop database: Runs on PC Multiuser
database: Supports multiple users at the same time Workgroup databases: Supports a small
number of users or a specific department Enterprise database: Supports many users across many
departments
9
Slide 10
Types of Databases
Centralized database: Data is located at a single site Distributed database: Data is distributed
across different sites Cloud database: Created and maintained using cloud data services that
provide defined performance measures for the database
10
Slide 11
Types of Databases
General-purpose databases: Contains a wide variety of data used in multiple disciplines
Discipline-specific databases: Contains data focused on specific subject areas Operational
database: Designed to support a company’s day-to-day operations
11
Slide 12
Types of Databases
,Analytical database: Stores historical data and business metrics used exclusively for tactical or
strategic decision making Data warehouse: Stores data in a format optimized for decision support
Online analytical processing (OLAP) Tools for retrieving, processing, and modeling data from the
data warehouse Business intelligence: Captures and processes business data to generate
information that support decision making
12
Slide 13
Types of Databases
Unstructured data: It exists in their original state Structured data: It results from formatting Structure
is applied based on type of processing to be performed Semistructured data: Processed to some
extent Extensible Markup Language (XML) Represents data elements in textual format
13
Slide 14
Database Design
Focuses on the design of the database structure that will be used to store and manage end-user
data Well-designed database Facilitates data management Generates accurate and valuable
information Poorly designed database causes difficult-to-trace errors
14
Slide 15
Evolution of File System Data Processing
15
Slide 16
Table 1.2 - Basic File Terminology
16
Slide 17
Figure 1.8 - A Simple File System
17
Slide 18
Problems with File System Data Processing
18
Slide 19
Structural and Data Dependence
, Structural dependence: Access to a file is dependent on its own structure All file system programs
are modified to conform to a new file structure Structural independence: File structure is changed
without affecting the application’s ability to access the data
19
Slide 20
Structural and Data Dependence
Data dependence Data access changes when data storage characteristics change Data
independence Data storage characteristics is changed without affecting the program’s ability to
access the data Practical significance of data dependence is difference between logical and
physical format
20
Slide 21
Data Redundancy
Unnecessarily storing same data at different places Islands of information: Scattered data locations
Increases the probability of having different versions of the same data
21
Slide 22
Data Redundancy Implications
Poor data security Data inconsistency Increased likelihood of data-entry errors when complex
entries are made in different files Data anomaly: Develops when not all of the required changes in
the redundant data are made successfully
22
Slide 23
Types of Data Anomaly
23
Slide 24
Database Systems
Logically related data stored in a single logical data repository Physically distributed among multiple
storage facilities DBMS eliminates most of file system’s problems Current generation DBMS
software: Stores data structures, relationships between structures, and access paths Defines,
stores, and manages all access paths and components
24
Slide 25
Figure 1.9 - Contrasting Database and File Systems
25
Slide 1
Chapter 1 Database Systems
Slide 2
Learning Objectives
In this chapter, you will learn: The difference between data and information What a database is, the
various types of databases, and why they are valuable assets for decision making The importance
of database design How modern databases evolved from file systems
2
Slide 3
Learning Objectives
In this chapter, you will learn: About flaws in file system data management The main components of
the database system The main functions of a database management system (DBMS)
3
Slide 4
Data versus Information
Data
Information
Raw facts Have not yet been processed to reveal their meaning to the end user Building blocks of
information Data management Generation, storage, and retrieval of data
Produced by processing raw data to reveal its meaning Requires context Bedrock of knowledge
Should be accurate, relevant, and timely to enable good decision making
4
Slide 5
Introducing the Database
Shared, integrated computer structure that stores a collection of: End-user data - Raw facts of
interest to end user Metadata: Data about data, which the end-user data are integrated and
managed Describe data characteristics and relationships Database management system (DBMS)
Collection of programs Manages the database structure Controls access to data stored in the
database
5
Slide 6
Role of the DBMS
,Intermediary between the user and the database Enables data to be shared Presents the end user
with an integrated view of the data Receives and translates application requests into operations
required to fulfill the requests Hides database’s internal complexity from the application programs
and users
6
Slide 7
Figure 1.3 - The DBMS Manages the Interaction between the End User and the Database
7
Slide 8
Advantages of the DBMS
Better data integration and less data inconsistency Data inconsistency: Different versions of the
same data appear in different places Increased end-user productivity Improved: Data sharing Data
security Data access Decision making Data quality: Accuracy, validity, and timeliness of data
8
Slide 9
Types of Databases
Single-user database: Supports one user at a time Desktop database: Runs on PC Multiuser
database: Supports multiple users at the same time Workgroup databases: Supports a small
number of users or a specific department Enterprise database: Supports many users across many
departments
9
Slide 10
Types of Databases
Centralized database: Data is located at a single site Distributed database: Data is distributed
across different sites Cloud database: Created and maintained using cloud data services that
provide defined performance measures for the database
10
Slide 11
Types of Databases
General-purpose databases: Contains a wide variety of data used in multiple disciplines
Discipline-specific databases: Contains data focused on specific subject areas Operational
database: Designed to support a company’s day-to-day operations
11
Slide 12
Types of Databases
,Analytical database: Stores historical data and business metrics used exclusively for tactical or
strategic decision making Data warehouse: Stores data in a format optimized for decision support
Online analytical processing (OLAP) Tools for retrieving, processing, and modeling data from the
data warehouse Business intelligence: Captures and processes business data to generate
information that support decision making
12
Slide 13
Types of Databases
Unstructured data: It exists in their original state Structured data: It results from formatting Structure
is applied based on type of processing to be performed Semistructured data: Processed to some
extent Extensible Markup Language (XML) Represents data elements in textual format
13
Slide 14
Database Design
Focuses on the design of the database structure that will be used to store and manage end-user
data Well-designed database Facilitates data management Generates accurate and valuable
information Poorly designed database causes difficult-to-trace errors
14
Slide 15
Evolution of File System Data Processing
15
Slide 16
Table 1.2 - Basic File Terminology
16
Slide 17
Figure 1.8 - A Simple File System
17
Slide 18
Problems with File System Data Processing
18
Slide 19
Structural and Data Dependence
, Structural dependence: Access to a file is dependent on its own structure All file system programs
are modified to conform to a new file structure Structural independence: File structure is changed
without affecting the application’s ability to access the data
19
Slide 20
Structural and Data Dependence
Data dependence Data access changes when data storage characteristics change Data
independence Data storage characteristics is changed without affecting the program’s ability to
access the data Practical significance of data dependence is difference between logical and
physical format
20
Slide 21
Data Redundancy
Unnecessarily storing same data at different places Islands of information: Scattered data locations
Increases the probability of having different versions of the same data
21
Slide 22
Data Redundancy Implications
Poor data security Data inconsistency Increased likelihood of data-entry errors when complex
entries are made in different files Data anomaly: Develops when not all of the required changes in
the redundant data are made successfully
22
Slide 23
Types of Data Anomaly
23
Slide 24
Database Systems
Logically related data stored in a single logical data repository Physically distributed among multiple
storage facilities DBMS eliminates most of file system’s problems Current generation DBMS
software: Stores data structures, relationships between structures, and access paths Defines,
stores, and manages all access paths and components
24
Slide 25
Figure 1.9 - Contrasting Database and File Systems
25
