1. Chapter 12: Databases

2. Competencies (Page 1 of 2)
Distinguish between the physical and logical views of data
Describe how data is organized: characters, fields, records, tables, and databases
Define key fields and compare batch versus real-time processing
Describe databases, including the need for databases, and database management systems (DBMS)

3. Competencies (Page 2 of 2)
Describe the five common database models: hierarchical, network, relational, multidimensional, and object-oriented.
Distinguish among individual, company, distributed, and commercial databases.
Discuss strategic database uses and security concerns.

4. Introduction to Databases
Like a library, secondary storage is designed to store information
End users need to understand
How such stored information is organized using data field, records, files and databases
The different types of databases and structures
Competent end users need to be able to find information that is stored in databases

5. Data Examples of data include Two ways to view data
Facts or observations about people, places, things, and events
Audio, music, photographs, and video
Two ways to view data
Physical view
Logical view
There are two ways to view data
Physical view – actual format and location; usually only very specialized computer professionals are concerned with the physical view
Logical view – focuses on the meaning and content of the data; end users and most computer professionals are concerned with this view

6. Data Organization Character Field Record File Table Database Key Field
Batch Versus Real-Time Processing
Understanding how data files work means understanding data organization, key fields (Key Term), batch versus real-time processing (Key Term), master versus transaction files and file organization.
Less complex to more complex:
character – basic logical data element; a single letter, number, or special character such as a punctuation mark
field – next higher level; group of related characters; Last Name for example; a data field represents an attribute (Key Term) (description or characteristic) of an entity (Key Term) (person, place, thing, or object (Key Term))
record – a collection of related fields
file – a collection of related records
table – a collection however a table typically does not include all the records or fields from one file; additionally a table can include records from more than one file
database – is an integrated collection of logically related records or objects
Key field – unique identifier to help locate data based on specific requests
Two main ways to process data: batch and real-time

7. Key Field Unique identifier also known as primary field
Common examples
Social Security Number
Student Identification Numbers
Employee Identification Numbers
Part Numbers
Inventory Numbers
This field contains unique information, so that each record can be distinguished from any other
Used to integrate data and helps with finding records, sorting records, compiling information contained in the database

8. Batch Processing Batch processing
Data is collected over a period of time and the processing happens later all at one time
Batch processing – data collected and stored over time (several hours, days, or even weeks) and then processed at once as a “batch”
Example - Bank credit card billing
Even today mainframe time is dedicated to batch processing

9. Real-Time Processing Real-time processing
Also known as online processing because it happens immediately during the transaction
Also known as online processing (Key Term)
Occurs when data is processed at the same time the transaction occurs
Made possible by disk packs and direct access storage devices
Makes it possible to access the data quickly

10. Databases Collection of integrated data
Logically related files and records
Databases address data redundancy and data integrity
Need for databases
Database management
Data redundancy – many organizations have multiple files on the same subject or person; for example, records for the same customer may appear in different files across multiple departments
Data integrity – accurate updating of files

11. Need for Databases Sharing Security Less data redundancy
Data integrity
The advantages of having/using a database are:
Sharing – in organizations, information in one department can readily be shared with others
Security – Users are given passwords or access only to the kind of information they need
Less data redundancy – decrease of unnecessary duplication of data (or data redundancy) when several departments use the same database of information
Increased data integrity - Reduced likelihood of inconsistent, incomplete, or inaccurate data – data lacking integrity

12. Database Management DBMS engine Data definition subsystem
Data dictionary
Data manipulation subsystem
Query-by-example
Structured query language (SQL)
Application generation subsystem
Data administration subsystem
Database management systems (DBMS) – enable users to create, modify, and gain access to data
DBMS engine – provides the bridge between the logical and physical view of the data; when users request data, the DBMS engine handles the details of actually locating the data
Data definition subsystem – defines the logical structure of the database by using a data dictionary (Key Term)
Data dictionary – contains a description of the structure of data in the database
Data manipulation subsystem – provides tools for maintaining and analyzing data; maintaining data is also known as data maintenance (Key Term); query language: most common method (Key Term) to access database; ask a question of database to find data; two common forms
Query-by-example
Most common query language is SQL (structured query language)
Application generation subsystem – provides tools to create data entry forms and specialized programming languages that interface with common and widely used programming languages
Data administration subsystem – helps manage the overall database; including maintaining security, providing disaster recovery support, and monitoring the overall performance of database operations
Larger organizations typically employ database administrators (DBAs) (Key Term), highly trained computer specialists to interact with the data administration subsystem; additional duties include determining processing rights (Key Term) or determining which people have access to what kinds of data in the database

13. DBMS Structure
DBMS programs are designed to work with data that is logically structured or arranged
Data models define rules and standards for data in a database
Five common data models are
Hierarchical database
Network database
Relational database
Multidimensional database
Object-oriented database
Purpose of database is to integrate individual items of data into useful information; can be done sequentially, directly, or index-sequentially
Databases can be organized differently to best fit their use: hierarchical; network; relational; multidimensional; and object-oriented;
Each of the next five slides displays and explains the different data models

14. Hierarchical Database
Fields or records are structured in nodes
Nodes are points connected like branches
One parent per node; a parent has several child nodes (one-to-many relationship)
Fields or records structured in nodes; viewed as branches of an upside-down tree
Each item is subordinate to its parent node (Key Term); only one parent per node; parent can have several child nodes; sometimes described as a one-to-many relationship
The subordinate item is the child node to the parent
If parent node is deleted, all the child nodes are deleted
New parent node must be created before adding new child node
Limited by rigid structure; no connection between the child nodes
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15. Network Database Hierarchical node arrangement
Each child node may have more than one parent node (many-to-many relationship)
Additional nodes are called pointers
Nodes can be reached through multiple paths
Also has hierarchical node arrangement -- but here child nodes may have more than one parent node, or a many-to-many relationship
The interconnected design allows for access via multiple pathways; i.e., more flexible
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16. Relational Database Data stored in table called a relation
Tables consist of rows and columns
Tables related via a common data item
No pre-determined access paths – Data stored in a collection of columns and rows called a table, or a relation
Tables may be electronically linked via a key field containing common data item
Most valuable feature of relational database (Key Term): simplicity
Entries can be easily added, deleted, and modified
Common for microcomputers:
Access, Paradox, dBASE, R: Base
Widely used for mainframe and minicomputer systems
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17. Multidimensional Database
A variation and an extension of the relational model to include additional dimensions, sometimes called a data cube
Good for representing complex relationships
Advantages over relational
Conceptualization
Processing speed
Includes additional or multiple dimensions called a data cube
Data can be viewed as a cube having three or more sides and consisting of cells
Each side is considered a dimension of the data
Used for complex relationships between data
Complex relationships between data can be represented and efficiently analyzed
Conceptualization – provide users with an intuitive model in which complex data and relationships can be conceptualized
Processing speed – analyzing and querying a large multidimensional database (Key Term) is faster
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18. Object-Oriented Database
Works with unstructured data
Photographs
Audio
Video
Objects contain both data and instructions
Organize using objects, classes, entities, attributes, and methods
Objects – entities that contain both data and action that can be taken on that data
Classes – are similar objects grouped together
Entities – person, place, thing, or event that is to be described
Attributes – the description of entities; similar to fields
Methods – descriptions of how the data is to be manipulated
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19. Types of Databases Individual Company or shared Distributed Commercial
Four kinds of databases whether large or small, limited or widely accessible:
Individual
Company or shared
Distributed databases (Key Term)
Commercial databases (Key Term)

20. Individual Databases Also called a microcomputer database
Integrated file collection for one person usually under the person’s direct control
Generally stored on the user’s hard-disk drive or on a LAN file server
An individual database (Key Term) may be valuable if you are in sales. For example:
Would allow you to keep track of your customer base
Sales managers can track their salespeople and their performance
An advertising account executive could keep track of what work and how many hours to charge each client
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21. Company or Shared Databases
Usually stored on a central database server and managed by a database administrator
Users throughout a company can access the database through the company’s networks
Common operational database – contains details about the operations of a company and data that describes the day-to-day operations of the organization
Common user database – contains selected information both from the common operational database and from outside private databases.
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22. Distributed Databases
Database is located in a place or places other than where users are located
Typically, database servers on a client/server network provide the link between users and the distant data
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23. Commercial Databases
Generally an enormous database developed by an organization to cover particular subjects
Access is offered to the public or selected outside individuals for a fee
Most commercial databases are designed for organizational and individual use
Also referred to as information utilities or data banks
Examples of important commercial databases include:
CSI – offers consumer and business services, including electronic mail
Dialog Information Services – offers business information, as well as technical and scientific information
Dow Jones Interactive Publishing – provides world news and information on business, investments, and stocks
LexisNexis – offers news and information on legal, public records, and business issues
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24. Database Uses and Issues
Strategic uses
Special type of database called data warehouse
Data mining is used to search databases for information and patterns
Security
Databases are valuable
Protection necessary
Databases offer great opportunities for productivity; users must make constant effort to keep database reliable
Databases help users keep current and plan for the future, but keeping them secure is important.
Data collected from numerous sources
Stored in a data warehouse
By data mining, companies are looking for related information and patterns
Examples of available databases include the following:
Business directories
Demographic data
Business statistical information
Text databases
Web databases
Security may include armed guards to electronic verification of person through fingerprints or eye imaging
Special hardware and software called firewalls (Key Term) are often used by companies to control access to their internal networks
Security: electronic fingerprint scanner

25. Careers In IT Database administrators
Determine the most efficient ways to organize and access a company’s data
Responsible for database security and backing up the system
Employers look for individuals with
Bachelors degree in Computer Science
Technical experience
Database administrators can expect to earn $48,500 to $85,000 annually
Internships and prior experience with the latest technology are a considerable advantage for those seeking jobs

26. A Look to the Future Every Book Ever Written … at Your Fingertips
Massive amounts of digital storage are now available and affordable
Google Book Search contains millions of book
Ask students to use the Internet to find out more about the Google Book Search database
What are the challenges faced with maintaining such a large database

27. Open-Ended Questions (Page 1 of 2)
Describe the five logical data groups or categories.
What is the difference between batch processing and real-time processing?
Identify and define the five parts of DBMS programs.

28. Open-Ended Questions (Page 2 of 2)
Describe each of the five common database models.
What are some of the benefits and limitations of databases? Why is security a concern?
The same questions are listed in the textbook as Open-Ended questions for the students to read and answer.