1. DATABASES – I
IS 524
Dr. Chandra Amaravadi

2. IN THIS PRESENTATION.. Importance of databases
Real world concepts: entities, eclasses, attributes
Data model
Organization concepts
DBMS & DBMS activities and functions

3. NEED FOR DATABASES All organizations need to manage information
A church needs to maintain information on donations
A consulting company needs to manage its contacts
A doctor needs to know if a patient is allergic to a particular medication.
An airline exec needs to know occupancy on a flight.
Information is the lifeblood of an organization.

4. NEED FOR DATABASES..
To get information when we need it, it needs organization.
A database can be thought of as an organized collection of information.
What is information used for? What is it about?
Where does it orginate?

5. BASIC DATA CONCEPTS

6. REAL WORLD CONCEPTS Entities Entity Classes Attributes Data models
Database approach/philosophy

7. ENTITIES
Individual examples of things and objects are called entities. They are modelled only as a collection.

8. WE ARE MORE INTERESTED IN
Eclasses
has
has
Organization
customers
departments
has eclasses
has
product
Sales/vendor
Organization deals with many eclasses

9. ENTITY CLASSES HAVE PROPERTIES
Properties are called
attributes
customers
Departments
Dept. code, name, manager, budget
machines/
parts
Sales/vendors

10. DISCUSSION Classify the following as entity, entity class or attribute
John (as a person)
San Francisco (as name of a city)
Customer
Book
Store#
Customs
Microsoft
Microsoft employees
The book “The Second Machine Age”
Invoice
Production

11. SUMMARY OF CONCEPTS
Entity – Individual example of person, place or thing.
Entity Class – Collection of related entities.
Attributes – Properties of entity classes about which we
would like to collect information.
Eclasses & attributes are used in developing data models

12. DATA MODELS (ER MODELS)
Abstract view of the data & relationships
Captures relationships between eclasses
Supports DB design & implementation
Relationship between students and courses?
between doctors and patients?
between teams and players?

13. DATA MODELS… Three types of relationships among entity classes A B A B
1:1
For each value of A, one
and only one value of B
and vice versa. A B
1:M A
For each value of A,
many values of B,
but for each B only one A. B
M:N A B
For each value of A,
many values of B and vice
versa.

14. DISCUSSION Identify the types of the following relationships
Company -- president
Instructor -- students
Flights -- pilots
City -- convention centers
Club -- members
Team – players (professional)
Company -- city
Books – authors
Artists -- records

15. THE DATA BASE APPROACH Entity classes File 1 File 2 Organization
cust.
File 2
emp.
Organization
Data model
Data base

16. BASIC ORGANIZATION CONCEPTS

17. BASIC ORGANIZATION CONCEPTS
data vs information
attribute
primary key
file
record
schema

18. DEFINING DATA Data: Data consists of raw facts e.g. 298-2034
USA China Russia Great Britain Germany Japan Australia France
Are raw facts useful? meaningful?

19. INFORMATION
Information: collection of facts, data presented in a context, elaboration of data.
Country
Gold
Silver
Bronze
Total
USA 46 29
104
China 38 27 23 88
Russia 24 26 32 82
Great Britain 17 19 65
Germany 11 14 44
Japan 7
Australia 16 12 35
France 34

20. INFORMATION AS A COLLECTION OF FACTS
Name: Chris Nash
DOB:
Profession: Engineer
Address: Walnut street.
Details describe a person
more. They are called ______

21. NOTION OF A RECORD Collection of facts is called a ________
Acct#:
Date: /5/14
Time: :48 pm
Merchant: WIU Union
Card type: Master Card
Issuer: First Bank
It is actually a collection
of __________ values

22. ONE ATTRIBUTE HAS A UNIQUE VALUE
Which of these has a unique value?
Acct#:
Date: /5/14
Time: :48 pm
Merchant: WIU Union
Card type: Master Card
Issuer: First Bank
The unique attribute is
called ___________.
3300
3305
3313

23. ORGANIZATION OF DATA/ INFORMATION Transaction#: 55643 Date: 12/5/15
Time: :08 pm
Merchant: Vitales
Card type: Master Card
Issuer: First Bank
Transaction#:
Date: /6/15
Time: :10 pm
Merchant: WIU Union
Card type: Master Card
Issuer: First Bank
Observations about these two “units” of data?

24. TRADITIONAL CONCEPT OF A FILE
Assume the following is stored somewhere,
Western Illinois University strives to maintain a community which values academic excellence; institutional integrity; and justice, equity, and diversity. Such an environment is essential in fostering the intellectual growth and personal development of all students. Each member of the University community shares responsibility in maintaining conditions which support the University's purpose. The Code of Student Conduct is designed to provide basic guidelines to advance the University's mission as a premier educational institution.
A traditional file is a collection of characters

25. CONCEPT OF A DATABASE FILE
Transaction#:
Date: /5/15
Time: :08 pm
Merchant: Vitales
Card type: Master Card
Issuer: First Bank
Transaction#:
Date: /6/15
Time: :10 pm
Merchant: WIU Union
Card type: Master Card
Issuer: First Bank
Transaction ID
Date
Time
Merchant
55643
12/05/15
4:08 pm
Vitales
55644
12/06/15
4:10 pm
WIU Union
A database file consists of _________________ .

26. DATABASE ORGANIZATION
Structure/schema
Attributes/field names
Primary key
PROD#
DESCR.
PRICE
QUANTITY
IR888E
Refrigerator
$1,800 20
TS3233
Television
$67 32
Record
Record
A database is organized into ______, _________ and _______.
attr. values

27. DATABASE ORGANIZATION..
PRIMARY KEY (FYI)
Also referred to as a key
Every table should have one
Generally short and a number
Value should be unique in a table; in other words ____ ?
Can be one attribute or a combination
listed as left most attribute
E.g. SS#, id#, vin#, isbn#

28. DATABASE ORGANIZATION
Database – A group of related files; collection
of information
File/table – A group of related records
Record – a grouping of related field values
Attribute – property e.g. hair color
Schema -- This is the logical view
of the database (tables and fields)
Primary key – An attribute whose values are
unique within a file
Secondary key – Any other attribute
DBMS – software program to provide controlled data access
Database
Files/tables
Records
Attr. values

29. DBMS

30. DBMS
DBMS - SW program to create, manage and provide controlled access to the data
Example Access, Oracle, DB2
What can we do with a DBMS?

31. DBMS ACTIVITIES & FUNCTIONS
Activities with DBMS
Define structure/schema
Data entry
Modify data
query data
get reports

32. DATA DEFINITION Define structure/schema
Field Name
Data type
Description
Length
Decimals
Prod#
Numeric
Unique prod code 6
Descr
Text
Short prod
description 25
Price
Currency
Product price 2
Attributes and data types (and other characteristics) are specified as part of data definition

33. DATA ENTRY Product #: Description: A form is used to enter data
Heading
PRODUCT DATA ENTRY
Label
Product #:
Description:
Field
Data entry form

34. MODIFY DATA
Modify data
Add
Delete
Change
Records/field values

35. Query by example (QBE) form
QUERYING DATA -QBE
Can use QBE or SQL to query data
list products costing less than $200
prod#
descr.
price
quantity
< 200
Query by example (QBE) form
list employees in finance department
e_ssn
ename
edept
e_join_dt
“finance”

36. RETRIEVAL WITH SQL
The structured query language can be used instead of QBE
Each SELECT statement has three parts
SELECT, FROM and WHERE
SELECT is used to select output attributes
FROM is used to specify the source tables
WHERE is used for row selection criteria
e.g. price < 400; zip = etc.
SELECT <attr. list>
FROM <tables>
WHERE <condition1 AND/OR condition 2…>

37. RETRIEVAL WITH SQL.. Reservation RESULT SQL QUERY Flt# Confirm#
Pname
Confirm#
AA1802
Smith
PA5R2
PA802
LX5R2
UA3702
Mahoney
ZB46A
RESULT
SQL QUERY
Flt# Confirm#
AA PA5R2
PA LX5R2
Select Flt#, Confirm#
From Reservation
Where Pname = “Smith”;

38. ANOTHER EXAMPLE What is the result of the query?
SELECT flt#, deptime, arrtime
FROM ??
WHERE depcity = "PHX" and destcity = "ORD";
FLIGHTS
flt #
depcity
destcity
deptime
arrtime
AA 802
PHX
ORD
1:51 AM
6:05AM
UA 3702
COS D
7:35 AM
8:05 AM
AA 812
SEA
4:55 AM
9:00 AM
D 42
5:40 PM
9:15PM
UA775
DFW
STL
4:45 PM
5:30 PM
What is the result of the query?

39. DISCUSSION Write SQL queries to list: 1) employee names.
2) Employees who live in Macomb.
3) employees who enjoy soccer.
Emp
EID
eName
eAddr
eCity
423
Smith
100 Oak lane
Macomb
425
501
Johnson
1430 N. Park street
Rock Island

40. THE THEORY OF RETRIEVAL
Dept
dCode
dName
dMgr
Fin.
Finance
Jon
Sas
Sales and service
Ross
Acc.
Accounts
Jan
DEPTS.
have
EMPLOYEES
Emp
EID
eName
eAddr.
11893
Jon
100 Oak street
11895
Carey
15 Candy lane
11896
Ross
1317 Fox creek
list EID, eName, dName

41. RETRIEVAL FROM MULTIPLE TABLES
When data is retrieved from multiple tables, it is called a multi-table query
Attr. From different tables are linked
primary key in one table
cross-reference key in the other table
The linking is carried out in the “Where” part of a query

42. MULTI-TABLE SELECT STATEMENT
Used to retrieve data from more than one table
SELECT table1.attr1, table2.attr
FROM table1, table2,
WHERE table1.fkey = table2.fkey AND/OR
condition1 AND/OR ;
RULES
When there are multiple tables, attr. names preceded by table name.
“From” will have list of tables as usual.
The WHERE part will have values of common attr. equated
there can be more than one condition, connected by AND or OR
Using the rules above, write a query to list EID, eName, dName

43. GETTING DATA OUT.. A report specification RH Title PH Column Headings
PRODUCT LISTING
Title PH
Column
Headings
PRODUCT #
DESCR.
PRICE
Detail
Product #
Descr.
Price
Fields PF RF
Average Price
Footer
A report specification

44. GETTING DATA OUT.. PRODUCT LISTING PROD# DESCRIPTION PRICE
M Chair $
M Table $200.00
Average Price $153.00
A generated report

45. SUMMARY OF DBMS ACTIVITIES
Activities with DBMS
Define structure /schema
Enter data
modify data
query data
get reports

46. DBMS ARCHITECTURE D B M S Kernel Data Defn. SQL Prog. Language
Interface
Data
Diction-
ary
Screen/
Report
Gen.
Appln.
Gen.
D B M S Kernel
Export/Import

47. USEFULNESS OF DATABASES

48. USAGE OF DATA/INFORMATION
What if a customer wants know price of a shirt in a department store? Returns?
What if a manager wants to know what products were sold on a particular day?
Suppose we have detailed information on each and every transaction in a store, what can we do with that?

49. IMPORTANCE OF DBMS’s Operational Usage:
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?
Strategic Usage:
To analyze trends
Identify sales prospects

50. DISCUSSION QUESTIONS
A collection of information about machines and parts is called _____?
A collection of records is called________ ?
The smallest unit of data in a database is _________ ?
What is QBE apart from expansion of abbreviation?
How does QBE differ from SQL?
What does data definition mean?
Where would databases be used?
How are databases used?
Do databases deal with data or information?
What is a good database application?

51. THAT’S ALL FOLKS!