11

INTRO TO DATABASESPart I

IS 340

BY

CHANDRA S. AMARAVADI

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IN THIS PRESENTATION..

Data vs information Database organization

file, record, attribute/field DBMS activities and functions DBMS components Importance of databases

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DATA VS INFORMATION

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DEFINING DATA AND INFORMATION

Data: Data consists of raw facts e.g. 298-2034Information: Data presented in a context e.g. someone’s phone#Some more examples:a) IS340a) IS340 is a core course for BBA.

b) Joan Smithb) Joan Smith is an arts & sciences student

c) Score was 94-72c) Score in the Celtics-Bulls game was 94-72.

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DATA IS NOT USUALLY ISOLATED

Example information about a person

Name: Steve NashDOB: 2-4-1965 Profession: Basket ball playerAddress: 415 Walnut street.

These describe a personmore. They are called ????.

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ANOTHER EXAMPLE

Example information about a credit card transaction:

Date: 12/5/08Time: 4:48 pmMerchant: WIU UnionCard type: Master CardIssuer: First Bank

These describe a transactionmore.

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ONE ATTRIBUTE HAS A UNIQUE VALUE

One of these is always unique:

Acct#: 4555950Date: 12/5/08Time: 4:48 pmMerchant: WIU UnionCard type: Master CardIssuer: First Bank

The unique attribute iscalled ???

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CHARACTERISTICS OF DATA/INFORMATION

WHAT CAN WE SAY ABOUT THE TWO TYPES OF DATA?

Transaction#: 55643Date: 12/5/08Time: 4:08 pmMerchant: WIU UnionCard type: Master CardIssuer: First Bank

Transaction#: 55644Date: 12/5/08Time: 4:20 pmMerchant: VitalesCard type: Master CardIssuer: Midwest Bank

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CHARACTERISTICS OF DATA/INFORMATION…

Transaction

ID

Transaction

Date

Transaction

Time

Merchant

55643 12/05/08 4:08 pm WIU Union

55644 12/05/08 4:20 pm Vitales

Data is typically organized into ??Transaction#: 55643Date: 12/5/08Time: 4:08 pmMerchant: WIU UnionCard type: Master CardIssuer: First Bank

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Transaction

ID

Transaction

Date

Transaction

Time

Merchant

55643 12/05/08 4:08 pm WIU Union

55644 12/05/08 4:20 pm Vitales

HISTORICAL APPROACH TO DATA

55643 12/05/08 4:08pm WIU Union55644 12/05/08 4:20pm Vitales55644 12/05/08 4:20pm Vitales55646 01/07/09 8:05am Pizza Hut

55643 $25.60 MasterCard 55644 $38.00 Visa55644 $63.00 Visa55646 $55.00 American Express

This is called ___________ __________.

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FILE PROCESSING PROBLEMS

What problems did the file processing approachresult in?

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DATABASE ORGANIZATION

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Database - Organized collection of information DBMS - SW program to manage and provide

controlled access to the data

DEFINITIONS

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Database – A group of related filesFile/table – A group of related recordsRecord – a grouping of related fieldsField – a grouping of characters (one row)

Schema -- This is the logical view of the database (tables and fields)Primary key – An attribute whose values are unique within a file

Database

Files/tables

Records

Fields

DBMS ORGANIZATION

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Primary key

Record

Attr. values

Attributes/field namesStructure/schema

DBMS ORGANIZATION

PROD# DESCR. PRICE QUANTITY

IR888E Refrigerator $1,800 20

TS3233 Television $67 32Record

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DBMS ACTIVITIES

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DBMS ACTIVITIES & FUNCTIONS

Define structure / schema

Enter data

modify data

query data

get reports

Activities with DBMS

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Define structure/schema

DBMS ACTIVITIES & FUNCTIONS

Field Name Data type Description Length Decimals

Prod# Numeric Unique prod code

6 0

Descr Text Short prod

description

25 0

Price Currency Product price 6 2

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Enter data -- Create a data entry form

PRODUCT DATA ENTRY

Product #:

Description:

LabelField

Heading

Data entry form

DBMS ACTIVITIES & FUNCTIONS

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DBMS ACTIVITIES & FUNCTIONS

Add Delete Change

Modify data

Records/field values

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Query datalist products costing more than $2,000

Prod# Descr. Price Quantity

> 2,000

Query by example form

DBMS ACTIVITIES & FUNCTIONS

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RH

PH

Detail

FieldsPF

RF

PRODUCT LISTING

PRODUCT # DESCR. PRICE

Product # Descr. Price

Average Price

Title

Column

Headings

Footer

A report specification

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GETTING DATA OUT..

PRODUCT LISTING

PROD# DESCRIPTION PRICE

M100 Chair $ 50.00 M150 Table $200.00

Average Price $153.00

A generated report

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Activities with DBMS◦Define structure / schema◦ Enter data◦modify data◦ query data◦ get reports

DBMS components

D B M S Kernel

D B M S Kernel

Major Components of DBMS

Export/Import

Data Defn.Data Defn. SQLSQL

Prog. Language Interface

Prog. Language Interface

DataDiction-

ary

DataDiction-

ary

Screen/ReportGen.

Screen/ReportGen.

Appln.Gen.

Appln.Gen.

DBMS COMPONENTS..Data definition – the facility through which schema is defined. (how new tables are created).SQL interface – the facility through which SQL commands are typed in.Programming language interface – the facility which processes SQL commands embedded in application program. Also known

as the host language interface. Data dictionary – the facility that records details about the schema, reports, data entry forms etc.Screen & reports- the facility through which data entry screens and reports are created.Appln. Generation- the facility through which applications are created.Export/Import -- the facility through which files can be imported/exported in different DBMS formats.DBMS Kernel -- the actual programs which interact with the O/S and carry out data I/O.

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Suppose we have detailed information on each and every transaction in a store, what can we do with that?

What if a customer wants to return a shirt purchased in the store?

What if a manager wants to know what products were sold on a particular day?

USAGE OF DATA/INFORMATION

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To store and record information e.g. bal, price, grades etc. To retrieve information e.g. check#432 cashed? To report information e.g. daily sales To answer queries e.g. how many shoes were sold?

IMPORTANCE OF DBMS’s

Databases are used:

To analyze trends Identify sales prospects

Advanced uses:

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INTRO TO DATABASES - II

IS 340

BY

CHANDRA S. AMARAVADI

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DBMS EVOLUTION

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EVOLUTION OF DBMS

File processingsystems

Hierarchicalsystems

Relationalsystems

1 March 2002 Greece2 July 2003 Italy3 ……………..

Person

Photo1 Photo2Greece Italy

PhotoId

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EVOLUTION OF DBMS..

FILE PROCESSING SYSTEMS:

Data in the form of “flat files” (ascii files) Each program had its own specific files Data was duplicated across files.

A system where data was managed by the programin the form of flat files.

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EVOLUTION OF DBMS..PROBLEMS CAUSED BY FILE PROCESSING

Uncontrolled redundancy Poor data quality (a.k.a.?) Lack of data sharing

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HIERARCHICAL MODEL..

Structure is hierarchical (not flat) There are one or more root segments segments are linked hierarchically

Difficult to write queries but very efficient (fast)!

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HIERARCHICAL MODEL

NAME TOTAL_ENROLL NO_OF_PHD

ASNAME JOB_TITLE FNAME RANK DEGREE

(D) DEPARTMENT

(A) ADMIN-STAFF (F) FACULTY

What do you call this?

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Data organized into tablesData retrieved by using SQL, 4th GL

joins tables by equating values of cross reference keys.

RELATIONAL MODEL

8895 Smith 4/16/90 $35,000

8896 Farley 4/22/91 $300

8897 Gomez 1/10/00 $2,000

ACCT

ACCT# NAME DT. OPENED BALANCE

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THE DATABASE DEVELOPMENT APPROACH

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cust.

empl.

prod

Organization

Entity classes

Data model

File 2

File 1

Data base

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THE DATABASE CONCEPT..

Organizations need to collect and manage information. Typically this need can be summarized in terms of entity classes and their relationships Known as a (conceptual) data model/ER model ER model is converted to database model Implemented

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Integrated conceptualization Convert it to design Go through development

process

Different users/programs can share the information easily

Can access info via SQL Can get reports easilyDatabase

DBMS

Prog. 2Prog. 1

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CUSTOMER ACCTS. LOANS

CROSS REFERENCE

REPORT

ACCT. DATA LOAN DATA

GETTING INFORMATIONFROM FILE PROCESSING

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GETTING INFORMATIONFROM A DATABASE

ACCT# NAME DT. OPENED BALANCE

8895 Smith 4/16/90 $35,000

8896 Farley 4/22/91 $300

8897 Gomez 1/10/00 $2,000

ACCT

LID AMOUNT INT. RATE BALANCE

LOAN

9978 $6,000 6.0% $2,440

9978 $5,000 7.1% $5,000

9992 $1,000 8.5% $ 400

How canWe combinethese twoTables?

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DATA MODELS

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DATA MODELS -- BASIC CONCEPTSData models: representations of relationships among entity classes

Entity – Individual example of person, place or thing.Entity Class – Collection of related entities (eclass).Attributes – Properties of entity classes about which we would like to collect information.

Primary key -- An attribute whose values are unique within an entity class (pkey).

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DISCUSSION

San Francisco Tires Customer Book ISBN# Neon Peoplesoft Cust. balance Microsoft Microsoft employees Date of Birth Invoice

Classify the following as entity, entity class or attribute

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DATA MODELS…

Cardinality: Number of entities participating in a relationship

A B1:1

A B1:M

A BM:N

For each value of A, oneand only one value of Band vice versa.

For each value of A, multiple values of B, but for each B only one A.

For each value of A, many values of B and vice versa.

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DISCUSSIONIdentify the types of the following relationships

company -- presidentinstructor -- studentsplane -- pilotscity -- convention centersdepartment -- employeesteam -- playerscompany -- citybooks – authorscity -- subdivisionsproduct -- warranty

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AN EXAMPLE ER CHART

CUSTOMER

ORDERS

Places

Cust# Name

PRODUCTSAre for

ENTITY CLASS

ATTRIBUTE

RELATIONSHIP

Ord# Ord dt

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Draw Data Models (ER models) corresponding to the followingSituations:

Students take courses from professors

Clients can book one or more properties with a rental agency. Eachproperty can be booked by more than one client (for different dates).

Trains arrive and depart from platforms in train stations, corresponding to the cities that they stop in. A city can have many Stations.

Airlines operate a number of flights which arrive and depart fromGates. There could be several flights from a gate, but each flightis assigned only one gate. Each airline operates a gate or a set of Gates which are leased to them by the airport.

DISCUSSION

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Design a database for the following situation: Bellsouth, atelephone company needs a database to maintain records ofits automobiles, repairs, mechanics and special equipment neededto repair cars. Mechanics are assigned skill codes based on thetype of repairs they can carry out. For e.g. Class III mechanicscan perform reborings, engine overhauls and transmission repairs.The repair shops are located in 300 cities and towns throughout the state. Mechanics can be assigned to only one repair shop at atime. The application requires knowing what equipment is (fore.g. diagnostic equipment, hydraulic machinery) is at what locationand also the repairs carried out on each vehicle. For each vehiclethe application requires knowing its identification number, mileage and repair history.

DISCUSSION

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DISTRIBUTED ANDMULTI-MEDIA DATABASES,

DATA WAREHOUSES

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CENTRALIZED DATABASES

The database is in one physical location. All applications regardless of whether the clients are located in Seoul or Detroit need to access data from that physical location. What are the limitations?

Centralized databases

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DISTRIBUTED DATABASES

Replicated -- copies of the database maintained in multiple sites Partitioned -- database is physically divided into chunks

The data is physically stored in multiple geographical locations

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REPLICATED DATABASES..

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PARTITIONED DATABASES..

Emp ID Emp Name

11049 Cathy 200 Meadowbrook

Emp Address

11051 Richard 13 E. Willow

11054 Hugh 1400 E. Washington

……. …….. …………………..

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PARTITIONED DATABASES

The database is divided into chunks. What is the logical way of doing this? Different chunks are placed in different locations. All the locations are connected. What are the advantages and limitations?

The database is in multiple physical locations

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MULTI-MEDIA DATABASES

Emp ID Emp Name Emp. Picture Emp Address

A database that is able to handle multiple data types: Conventional information Images Audio & video

Capable of storing, retrieving and updating this type ofinformation

Emp.jpg

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MULTI-MEDIA DATABASES..

APPLICATIONS Travel bureaus Hospitals Manufacturing Training

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MULTI-MEDIA DATABASES..

Storage space Retrieval Modification

ISSUES

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DATA WAREHOUSE: Historical data organized for analysis and decision making.

DATA MART: smaller version of data warehouse, specialized by functional area e.g. marketing

ON-LINE ANALYTICAL PROCESSING (OLAP): organizes data into a “cube” for decision analysis.

DATA WAREHOUSES

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HISTORICALINFORMATION

INTERNALDATASOURCES

EXTERNALDATASOURCES

OPERATIONAL,HISTORICAL DATA

DATA WAREHOUSE

EXTRACT,TRANSFORM

OLAP

DATA MINING

DATA WAREHOUSING & OLAP

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DISCUSSION QUESTIONS

Are Databases and DBMSs one and the same? Does a record consist of files? What is the smallest unit of data in the database? Does data integrity refer to data quality? What does the detail line of a report consist of? Is an “employee” an entity class or an attribute? Is the data dictionary useful while creating the database? Why do we use SQL? Is it necessary to use SQL to produce database reports? If we have a number of diskettes in alphabetical

sequence, is this an example of a file organization? If so, what type? Would multi-national organizations prefer centralized databases?

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THAT’S ALL FOLKS!

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THAT’S ALL FOLKS!

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THAT’S ALL FOLKS!