Oracle_ch1.pptx

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Dr. Chen, Busin ess Database Systems

Chapter 1Overview of Database Concepts

Jason C.H. Chen,Ph.D.

Professor of MIS

School of Business, Gonzaga University

Spokane, WA 99258 USA

[email protected]


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Dr. Chen, Busin ess Database Systems 2

Objectives

Define database terms

Identify the purpose of a database managementsystem (DBMS)

Explain database design using entity-relationshipmodels and normalization

Explain the purpose of a Structured QueryLanguage (SQL)

Understand how this textbooks topics aresequenced and how the two sample databases areused


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Data vs. Information

Users really want is

Information

What users can learn from the data

how to satisfy their best customers

how to allocate their resources most efficiently,how to minimize losses


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Objectives of the MIS

Deliver the right information

to the rightpeople,

at the right time,with the right form.

Ultimately, MIS should

improve the workers

productivity.

whohas what

information about

whomand when,

where, and howwillall be decided in the

process of building

an information

system.


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A Relationship Between the Organization and

the DataBase

Organizational

IS Resources:

1. Hardware

2. Software

3. Data

4. Procedures

5. People

Picture

Or

Model

Old

State

Events

New

State

Activities

DataBase

Management

Systems D.B.

Transactions

(Add, modify, delete, )

Correspond with the

processing of the events

Information must be:

1. Time: Timely,

2. Content: Accurate, relevant, and verifiable.

3. Form: Presented in a useable form.

User

TM 0-6


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Questions

Is MS/Access or Oracle (SQL/Server or

IBM DB2) a data base?

Why dont we just create a huge data file

containing all fields (columns)?

Have you ever created a database (with many

applications) with only one huge data filecontaining all fields (columns)?


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Traditional File Processing Approach

Traditional File Processing

An application uses one specialized file. For example,

purchase order processing application uses data about

supplier and products, while an order-taking application uses

data about customer, products and orders.

Problems:

Data dependence: data structures are tightly coupled with

applications. In other words, we prefer data independence.

Data redundancy: same data are repeatedly saved for

different applications.

Other problems


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Types of Data Processing

Two types of data processing

File-based(traditional) data processing

applications developed by Java

Data-baseddata processing

applications developed by Oracle or MS/Access)


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Three file processing systems at a Furniture Company

Duplicate

Data

What is the main

problem in the

companys processingsystems?


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Disadvantages of File Processing

Program-Data Dependence All programs maintain metadata for each file they use

Data Redundancy (Duplication of data)

Different systems/programs have separate copies of the same

data

Limited Data Sharing

No centralized control of data

Lengthy Development Times Programmers must design their own file formats

Excessive Program Maintenance

80% of of information systems budget


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Database Management System

DBMS manages data

resources like an operatingsystem manages hardware

resources

DBMSDatabase

containingcentralizedshared data

Application#1

Application#2

Application#3

What are the advantages of employing

Data-based F ile Processing?


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Traditional File Processing

ProductSales rep

Supplier

Data Files

PurchasingSystem

Sales

order processingsystem

Product

Applications

Name, item#,

description...

Name, item#,

description...


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Database Management Systems

Product

Sales rep

Supplier

Database

Database

Management

Systems

PurchasingSystem

Sales

order processing

system


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Database Terminology

Databasean organized collection of

logically related data files

Database management system

(DBMS)software used to create

and interact with the database


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Relational Databases

Data is organized in tables

Columns (fields) represent different data categories

Rows (records) contain actual data values


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Database Example


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Components Example


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Relational Database Terms

Entity:an object about which you want to store data

Table, column, row

Flat file, attribute (or field), record

Relationships:links that show how different records arerelated

Key Fields: establish relationships among records indifferent tables

Five main types of key fields: primary keys candidate keys

surrogate keys

foreign keys

composite keys


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Primary Keys vs. Candidate Keys

Primary key

Value must be unique for each record

Serves to identify the record

Present in every record

Cant be NULL

Should be numeric

Candidate key

Any field that could be used as the primary key

Should be a unique, unchanging numeric field


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Surrogate Keys

Surrogate key: created to be the records primary keyidentifier when no suitable primary key exists

Surrogate key has no real relationship to the record towhich it is assigned, other than to identify the record

uniquely Developers configure the database to generate

surrogate key values automatically

In an Oracle database, you can automatically generate

surrogate key values using a sequence Surrogate keys are always numerical fields, becausethe database generates surrogate key valuesautomatically by incrementing the previous value byone


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Foreign Keys

Foreign key:a field in a table that is a primary key inanother table

Foreign key creates a relationship between the two tables

Foreign key value must exist in the table where it is aprimary key


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Composite Key

Composite key: a unique key that you create by

combining two or more fields

Usually comprised of fields that are primary keys

in other tables

ORDER_ID PRODUCT_ID ORDER_QUANTITY

100 1 2

100 2 2

200 2 2

200 1 1

CompositeKey


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Database Management System

Data storage: manage the physical structure of thedatabase

Security: control user access and privileges

Multiuser access: manage concurrent data access

Backup: enable recovery options for database failures

Data access language: provide a language that allowsdatabase access

Data integrity: enable constraints or checks on data Data dictionary: maintain information about database

structure


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The Oracle11g Client/Server Database

Oracle11gis the latest release of Oracle Corporationsrelational database management system

All Oracle server- and client-side programs use OracleNet, a utility that enables the network communicationbetween the client and the server


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Linking Internal Databases to the Web

DATABASE TRENDS

N


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Web-Based Client/Server Database Architecture

Network

Web server

Database Server

Web Browser5. Retrieved

data

4. Data

query

7. Data-based

Web page

8. Data-based

Web page

1. Request for

data-based Web page

6. Retrieved data

3. Data query

2. Request fordata-based Web page

Legend

CommunicationsBetween Web browser

And Web server

Communications

Between Web server

And database server


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System Response Time

Depends on ...

the speedof the network

the sizeof the database

the waythe database is used

a personal database running on a server

might handle 10 users making databasetransactions at the same time beforebecoming overloaded.


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Handling server and client failures

Processing transactions

Handling high data volumes

Providing security

Servicing multiple simultaneous users

Advantages of Client/Server Database

Management Systems


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SQL, SQL*Plus, and PL/SQL

Language or Tool Description

SQL A command language for communication with the

Oracle 10/11Server from any tool or application. OracleSQL contains many extensions.

SQL*Plus An Oracle tool that recognizes and submits SQL and

PL/SQL statements to the Server for execution andcontains its own command language.

PL/SQL An Oracle Procedural Language for writing applicationlogic and manipulating data outside the database.

SQL*PlusServer

Buffer

SQL and

PL/SQL

Scripts

Terminal


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Design Principles

To avoid creating tables that contain redundantdata, group related items that describe a singleentity together in a common table

Do not create tables that duplicate values manytimes in different rows

When creating a database and inserting datavalues, you must specify the data type for each

column Recall that primary key fields should use a number

data type to avoid typographical, punctuation, andcase variation errors


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Database Design

Systems Development Life Cycle (SDLC)

Entity-relationship model (E-R model)

Normalization


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Systems Development Life Cycle

Systems Implementation

Product:Operational System

Systems Investigation(Definition)Product:

Feasibility Study

Systems AnalysisProduct:

Functional Requirements

Systems DesignProduct:

System Specifications

Systems MaintenanceProduct:

Improved System

Understand theBusinessProblem orOpportunity

Develop anInformationSystemSolution

Implement

the InformationSystemSolution


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Systems Development Life Cycle

(SDLC)

Systems investigationunderstanding the problem

Systems analysisunderstanding the solution

Systems designcreating the logical and physical

components Systems implementationplacing completed system

into operation

including integration, testing and deployment

Systems maintenance and reviewevaluating the

implemented system


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Data Models

A data model is a collection of concepts fordescribing data.

CUSTOMER ORDER

Three database models

Hierarchical

Network

Relational


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E-R Model Notation Examples

Figure 1-3 E-R Model notation examples

Please note that the name of entity should be singular even it contains multiple

instances


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Figure 1-5 JustLee Books table structures after normalization


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One-to-Many Relationship

Each occurrence of data in one entity can be

represented by many occurrences of the

data in the other entity

Example: A class has only one instructor,

but each instructor can teach many classes

Class Instructor


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Many-to-Many Relationship

Data can have multiple occurrences in bothentities

Example: A student can take many classes,

and each class is composed of manystudents

Can not be included in the physical database

Class Student


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JustLee Example E-R Model


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Q C / h d b h f ll i bl


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ISBN TitlePublication

DateCost Retail Category Publisher Contact Author

8843172113 Database

Implementation

04-JUN-03 31.40 55.95 Computer American

Publishing

Davidson T.Peterson

8843172113 Database

Implementation


Publishing

Davidson J.Austin

8843172113 Database

Implementation


Publishing

Davidson J.Adams

1915762492 Handcranked

Computers

21-JUN-05 21.80 25.00 Computer Amercian

Publishing

Davidson W.White


Computers


Publishing

Davidson L.White

6522489652 Meaningful

Accounting

25-MAY-08 41.60 85.00 Accounting Articulate

Publishing

Brown M.Kane


Accounting


Publishing

Brown S. Little

Q: Can we create/enter the data base on the following table

immediately?

BOOKS table


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Database Normalization

Purposes

design a reliable and stable data bases

increase data integrity (reduce or control dataredundancy)

Processes

determines required tables and columns for

each table

multistep process


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Problem Solving for Modeling a Database Project

Business ProblemStudy and Analyze

w/Team

???

IMPLEMENTATION


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Problem Solving for Modeling a Database Project

Business ProblemStudy and Analyze

w/Team

ER or other Model

Normalization

(3NF)

User interview &

Integrated Model

Normalization

IMPLEMENTATION


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Well-Structured Relations

A relation that contains minimal data redundancyand allows users to insert, delete, and update rowswithout causing data inconsistencies

Goal is to avoid (minimize)anomalies

Insertion Anomalyadding new rows forces user tocreate duplicate data

Deletion Anomalydeleting rows may cause a loss ofdata that would be needed for other future rows

Modification Anomalychanging data in a row forceschanges to other rows because of duplication

General rule of thumb: a table should not pertain to more

than one entity type

F ti l D d i d K


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Functional Dependencies and Keys

Functional Dependency: The value of one attribute (thedeterminant) determines the value of another attribute.

Candidate Key

A unique identifier. One of the candidate keys will becomethe primary key

E.g. perhaps there is both credit card number and SS# ina tablein this case both are candidate keys

Each non-key field is functionally dependent on everycandidate key

Figure 5-9


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Unnormalized Data

Contains repeating groups in the Author columnin the BOOKS table


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First-Normal Form (1NF)

Primary key (pk) is identified

Repeating groups are eliminated

Every attribute value is atomic (singled-value)


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First-Normal Form (1NF) (continued)

ISBN and Author columns together create acomposite primary key

1NF: ISBN and Author fields together create a composite primary key


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8843172113 Database

Implementation


Publishing

Davidson T.Peterson

8843172113 Database

Implementation


Publishing

Davidson J.Austin

8843172113 Database

Implementation


Publishing

Davidson J.Adams


Computers


Publishing

Davidson W.White


Computers


Publishing

Davidson L.White


Accounting


Publishing

Brown M.Kane


Accounting


Publishing

Brown S. Little

1NF: ISBN and Authorfields together create a composite primary key

Q: What fields are dependent on ISBN alone ?


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Composite Primary Key

More than one field (column) is required to

uniquely identify a record (row).

Can lead to partial dependencya field isonly dependent on a portion of the primary

key


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Second-Normal Form (2NF)

1NF and everynon-key attribute is fully

functionally dependent on the primary key.

Partial dependency must be eliminatedBreak the composite primary key into two

parts, each part representing a separate table

Every non-key attribute must be defined by theentire key (either a single PKor a CK), not by

only part of the key


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Second-NormalForm (2NF) (continued)

BOOKS table in 2NF

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DateCost Retail Category Publisher Contact

8843172113 Database

Implementation


Publishing

Davidson


Computers


Publishing

Davidson


Accounting


Publishing

Brown

ISBN Author

8843172113 T.Peterson

8843172113 J.Austin

8843172113 J.Adams

1915762492 W.White

1915762492 L.White

6522489652 M.Kane

6522489652 S. Little

1NF: ISBN and Author fields together create a composite primary key


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8843172113 Database

Implementation


Publishing

Davidson T.Peterson

8843172113 Database

Implementation


Publishing

Davidson J.Austin

8843172113 Database

Implementation


Publishing

Davidson J.Adams


Computers


Publishing

Davidson W.White


Computers


Publishing

Davidson L.White


Accounting


Publishing

Brown M.Kane


Accounting


Publishing

Brown S. Little

1NF: ISBN and Authorfields together create a composite primary key

Q: What fields are dependent on ISBN alone ?

Fig: A Process from 1NF to 2NF


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ISBN Title PublicationDate

Cost Retail Category Publisher AuthorContact

Dependency on entire primary key (ISBN & Author)

Dependency on partial primary key (ISBN)



8843172113 DatabaseImplementation

04-JUN-03 31.40 55.95 Computer AmericanPublishing

Davidson T.Peterson

8843172113 Database

Implementation


Publishing

Davidson J.Austin

8843172113 Database

Implementation


Publishing

Davidson J.Adams


Computers


Publishing

Davidson W.White


Computers


Publishing

Davidson L.White


Accounting


Publishing

Brown M.Kane


Accounting


Publishing

Brown S. Little

Fig: A Process from1NF to 2NF


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g: ocess o N to N

ISBN & AuthorTitle, Publication Date, Cost

ISBNTitle, Publication Date, Cost

Therefore, NOT in 2ndNormal Form!!



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g



ISBN Author


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Figure 1-5 JustLee Books table structures after normalization

Fig re: 5 22 Steps in normali ation


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Table with Repeating

Group attributes

First normal

form (1NF)

Second normal

form(2NF)

Third normalform (3NF)

Boyce-Codd normal

form (BC-NF)

Fourth normalForm (4NF)

Fifth normal

form (5NF)

Remove Repeating

Group Attributes

Remove remaining

anomalies resulting from

multiple candidate keys

Remove Multivalued

Dependencies

Remove Remaining

Anomalies

Figure: 5-22 Steps in normalization

Remove Partial

Dependencies

Remove Transitive

Dependencies


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ISBN

TitleISBNPublication Date

ISBNCategory

ISBNPublisher

ISBNContactand

BUT

ISBNCategoryContact

implies

Transitive dependency

(not in 3rdNF)

ISBN Contact

CategoryContact

All this is OK

(2ndNF)

All non-key fields are dependent on pk (ISBN)

anon-key field is dep. on another

non-key field



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ISBN Title PublicationDate Cost Retail Category Publisher Contact


DateCost Retail Category Publisher

Category Contact


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Third-Normal Form (3NF)

Publisher contactname has been removed

TABLE 1-5 The BOOKS Table in 3NF

Category Contact

Computer Davidson

Accounting Brown



8843172113 Database

Implementation


Publishing


Computers


Publishing


Accounting


Publishing

We might further create a look up table

for Category (see Table 1-6, p.12)



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8843172113 Database

Implementation


Publishing

Davidson


Computers


Publishing

Davidson


Accounting


Publishin

g

Brown

Category Contact

Computer Davidson

Accounting Brown



8843172113 Database

Implementation


Publishing


Computers


Publishing

6522489652 MeaningfulAccounting

25-MAY-08 41.60 85.00 Accounting ArticulatePublishing


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Q: How many tables on the 3NF?


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DateCost Retail Category Publisher AuthorContact

ISBN Author

Category Contact



Q: How many tables on the 3NF?

Answer: Three tables. What are they?

Note that You cant do anyimplementation until you transform

a table into 3NF (with more tables

produced)

BOOKS

BOOK_AUTHOR

CATEGORY_CONTACT

Processes from 1NF 2NF 3NF


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Category Contact

Computer Davidson

Accounting Brown



8843172113 Database

Implementation


Publishing


Computers


Publishing


Accounting


Publishing

ISBN Author

8843172113 T.Peterson

8843172113 J.Austin

8843172113 J.Adams

1915762492 W.White

1915762492 L.White

6522489652 M.Kane

6522489652 S. Little



8843172113 Database

Implementation


Publishing

Davidson T.Peterson

8843172113 Database

Implementation


Publishing

Davidson J.Austin

8843172113 Database

Implementation


Publishing

Davidson J.Adams


Computers


Publishing

Davidson W.White


Computers


Publishing

Davidson L.White


Accounting


Publishing

Brown M.Kane


Accounting


Publishing

Brown S. Little

Category Code Category

10 Computer

50 Accounting

fk(foreign key)

We will learn all detailed processes in the main text (ch.4)


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Summary of Normalization Steps

1NF: eliminate repeating groups, identify

the primary key

2NF: table is in 1NF, and partialdependencies are eliminated

3NF: table is in 2NF, and transitive

dependencies are eliminated

Figure: 5-22 Steps in normalization


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Table with Repeating

Group attributes

First normal

form (1NF)

Second normal

form(2NF)

Third normal

form (3NF)

Boyce-Codd normal

form (BC-NF)

Fourth normal

Form (4NF)

Fifth normal

form (5NF)

Remove Repeating

Group Attributes

Remove remaining

anomalies resulting from

multiple candidate keys

Remove Multivalued

Dependencies

Remove Remaining

Anomalies

g p

Remove Partial

Dependencies

Remove Transitive

Dependencies


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Relating Tables within the Database

Once tables are normalized, make certain

tables are linked

Tables are linked through a common field A common field is usually a primary key in

one table and a foreign key in the other

table


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Category

Contact

Category_Contact


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Structured Query Language (SQL)

Data sublanguage

Used to:

Create or modify tablesAdd data to tables

Edit data in tables

Retrieve data from tables ANSI and ISO standards

Databases Used in this Textbook


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Databases Used in this Textbook

JustLee Books Database

Assumptions

No back orders or partial shipments

Only U.S. addressesCompleted orders are transferred to the annual

SALES table at the end of each month to enable

faster processing on the ORDERS table

T i S


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Topic Sequence

The first half of the text will focus on

creating a database

The second half of the text will focus onquerying or retrieving data from a database

Summary


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Summary

A DBMS is used to create and maintain a database

A database is composed of a group of interrelated tables A file is a group of related records; a file is also called a table in the

physical database

A record is a group of related fields regarding one specific entity; a

record is also called a row A common field is used to join data contained in different tables

A primary key is used to uniquely identify each record

A foreign key is a common field that exists between two tables butis also a primary key in one of the tables

A lookup table is a common term for a table referenced in a foreignkey

A Structured Query Language (SQL) is a data sublanguage thatnavigates the data stored within a databases tables

S ( ti d)


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Summary (continued)

A record is considered unnormalized if it contains repeatinggroups

A record is in first-normal form (1NF) if no repeatinggroups exist and it has a primary key

Second-normal form (2NF) is achieved if the record is in1NF and has no partial dependencies

After a record is in 2NF and all transitive dependencies havebeen removed, then it is in third-normal form (3NF), whichis generally sufficient for most databases

Homework: Transform it into 3NF


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SALES relation with simple data

Cust_ID Name Salesperson Region

8023 Anderson 101 South

9167 Bancroft 102 West

7924 Hobbs 101 South

6837 Tucker 103 East

8596 Eckersley 102 West

7018 Arnold 104 North

SALES

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