Chapter 4 Database Management Systems. Chapter 4Slide 2 What is a Database Management System (DBMS)? Database An organized collection of related data

Chapter 4Chapter 4

Database Management

Systems

Chapter 4 Slide 2

What is a DatabaseManagement System (DBMS)?What is a DatabaseManagement 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 non-programming users

Chapter 4 Slide 3

Storing and Retrieving Data• The database sees the physical view of

the dataHow 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

Functions of A Database Management System


Chapter 4 Slide 4

Storing and Retrieving Data• The database presents a logical view to

the user and programmerOrganizes and presents data elements in ways

that managers and other users find helpful

Functions of A Database Management SystemFunctions of A Database Management System



Chapter 4 Slide 5

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 6

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 7

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 8

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 9

Providing Backup and Recovery Services• Databases cannot be backed up like files

because they are too large and in constant use

• Backup techniques includeOperating in parallel on two storage devices Use of temporary database during backup




Chapter 4 Slide 10

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 11

Enforcing Business Rules• A DBMS enforces rules that ensure related

data are logically consistent



Chapter 4 Slide 12

Database ApplicationsDatabase 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 13


Data Warehouse• An enterprise-wide database designed to

support business intelligence and management decision making rather than operational needs

Chapter 4 Slide 14

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 15

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 16

Data Design • The process of identifying and formalizing

the relationships among the elements of data that will form an organization's database

Developing Databases through Data Design


Chapter 4 Slide 17

[Insert Figure 4-4 here]



Chapter 4 Slide 18

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 19

The Entity-Relationship Model

The Entity-Relationship Model

Figure 4-5

Chapter 4 Slide 20

Technological UnderpinningsTechnological Underpinnings

Distribution Architecture• Refers to how the organization distributes

data and database processing physically among the computers in a network

Chapter 4 Slide 21

Types of Distribution Architectures• Decentralized architecture

Involves no data sharing

• Centralized architectureHas a single DBMS running on a single

computer and maintaining data centrally


Chapter 4 Slide 22

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 23

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 architectureUtilizes more than one architecture


Chapter 4 Slide 24

Database Models• Relational model

A table represents a file with rows called tuples and columns called attributes


Chapter 4 Slide 25

Technological Underpinnings

[Insert Figure 4-8 here]

Chapter 4 Slide 26

Database Models• Object model

Derives from object-oriented programming Object-oriented DBMSs store objects and

object-class metadata


Chapter 4 Slide 27

Database Models• XML model

A language used to mark and identify components of Web-based transaction documents


Chapter 4 Slide 28

Database Models• Network model

Builds a tighter linkage between elements of data

• Hierarchical modelA precursor to the network model, as a network

model with additional restrictionsViews data as organized in a logical hierarchy


Chapter 4 Slide 29

Managing the Data ResourceManaging 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

End of Chapter 4End of

Chapter 4

Database Management

Systems

Documents

Chapter 4 Database Management Systems. Chapter 4Slide 2 What is a Database Management System (DBMS)? Database An organized collection of related data