1. Spring 2013 CS 103 Computer Science – Business Problems Lecture 11: Database Management System
Instructor: Zhe He
Department of Computer Science
New Jersey Institute of Technology
1/11/2019

2. Database Management Systems
Database management system (DBMS)
Store large collections of data
Organize the data
Becomes a data storage system
Discussion point
Ask your student if anyone knows why sorting by zip code is important. Hopefully, someone knows that the post office provides a discount on presorted mail.

3. The Database Stores a collection of related items
Collection is arranged in a structure
Organizes and describes the data
Often includes helper documents
Two different types
Teaching tip
Figure 11A.2 on page 423 describes the database structure

4. Database Structure
Field Name
Record
Field

5. The Database Fields Hold an individual piece of data
Are named descriptively
Often called a column
Phone book examples
Name, address, , phone number
Fields may contain no data
Last Name
Smith
Lin
Luis

6. The Database Records One full set of fields Often called a row
Databases may have unlimited rows
Last
Name
First Name
Address
Phone #
Smith
Joe
10 Harrison Ave, Harrison, NJ
Lin
Ying
30 fork Str, Newark, NJ
Luis Hu
12 Rose Str, Kearny, NJ

7. The Database Tables One complete collection of records
Databases may have thousands of tables
Last
Name
First Name
Address
Phone #
Smith
Joe
10 Harrison Ave, Harrison, NJ
Lin
Ying
30 fork Str, Newark, NJ
Luis Hu
12 Rose Str, Kearny, NJ

8. Flat-file Databases Typically has only one table
If multiple, each has a separate file
Useful for simple data storage needs
Hard to manage large data needs
Can waste disk space
Teaching tip
Start your students thinking about real databases, with millions of records. Using PA instead of Pennsylvania saves 10 bytes per record. In a database with 1 million records, this saves 10,000,000 bytes. This is roughly equal to a stack of 10 floppy disks

9. Relational Databases Made of two or more tables
Tables are related by a common field
Called a relationship or join
Can help organize data
Most common form of database
Maintaining data is easier than flat-file
No wasted disk space
Teaching tip
To demonstrate the power of relationships, setup a flat file database with music, artists, CD and year released. Demonstrate how difficult and wasteful it is to store several songs by the same artist and CD. Be sure to make several typing mistakes. Then build the same structure relationally. Create music, artist and CD tables. Join the artist and CD to the music table. Now show how easy it is to add songs from the same CD. While creating this database, it helps to use music the students know.

10. Symbols on ER Diagram ssn Person name Wedding Is-insured Entity Type
Attribute
Is-insured
Relationship
Type
Wedding
Weak
Entity Type
ssn
Key Attribute

11. ER Diagram degree department gender room name Student CID name time
Course
UCID
department
credits
Teach
Take
gender
name
UCID
degree
Instructor

12. Cardinality in E-R diagram
One-to-one (1:1) 1 1
Marry
Man
Woman
One-to-many (1:n) 1 M
Fulfill
Order
Customer
Many-to-many (n:m) M N
Take
Student
Course
NOTE: Every many to many relationship consists of two one to
many relationships working in opposite directions

13. ER Diagram cont. degree department gender room name Student CID name
time
Course M
UCID
department N N
credits
Teach
Take 1
gender
name
UCID
degree
Instructor

14. Full participation degree department gender room name Student CID name
time
Course M
UCID
department N N
credits
Teach
Take 1
gender
name
UCID
degree
Instructor

15. ER Diagram

16. The DBMS Programs that control the database Allows
Entering data
Querying data
Printing reports
Supports thousands of users
Includes tools to protect the data
Teaching tip
Protecting databases is similar to network administration, covered in chapter 9. Access to read and change data is limited to a list of allowed users.

17. Working with a Database
Creating tables
List the necessary fields
Steps to define a field
Descriptively name the field
Specify the field type
Determine the field size

18. Working with a Database
Field types
Describes the type of data stored
Most DBMS use the same types
Text fields store letters and numbers
Numeric field store numbers
Date and time field
Logical field stores yes or no
Binary field stores images or sounds
Counter field generates sequential numbers
Memo fields store large amounts of data
Teaching tip
Dates are stored sequentially in a database. 0 is January 1, 1970 at midnight. 1 is one millisecond after midnight on January 1, Each date represents the number of milliseconds from January 1, 1970.

19. Working with a Database
Entering data into a table
Users type data into a field
Data must be entered accurately
Constraints help to verify data
Forms are typically used for data entry

20. Working with a Database
Viewing records
Datasheet view shows all records
Filters can limit the records shown
Display only records matching a criteria
Forms allow viewing one record

21. Working with a Database
Sorting records
Order records based on a field
Multiple sub sorts resolve ‘ties’
Several types of sorts
Alphabetic
Numeric
Chronological
Ascending
Descending
Teaching tip
Using a DBMS, demonstrate the power of sorting for the class.

22. Working with a Database
Querying a database
Statement that describes desired data
List of fields can be modified
Uses of querying
Find data
Calculate values per record
Delete records
Most important DBMS skill
Teaching tip
Page 432 and 433 show examples of the different querying languages.

23. Working with a Database
Query languages
All DBMS use a query language
Most DBMS modify the language
Structured Query Language (SQL)
Most common query language
xBase
Query language for dBase systems
Query by example (QBE)
Interface to SQL or xBase
Interactive query design

24. Query Examples SQL xBase Select FirstName, LastName, Phone
From tblPhoneNumbers
Where LastName=“Norton”;
xBase
Use tblPhoneNumbers
List FirstName, LastName, Phone
For LastName=“Norton”

25. Query Examples degree department gender room name Student CID name
time
Course M
UCID
department N N
credits
Teach
Take 1
gender
name
IID
Instructor

26. Mapping 1. Entities Student (UCID, name, gender, degree, department)
Course (CID, name, room, time, department, credits)
Instructor (IID, name, gender)

27. Mapping 2. M-N Relationships 3. N-1 Relationships (full participation)
Take (UCID, CID)
3. N-1 Relationships (full participation)
Course (CID, name, room, time, department, credits, IID)

28. Schema from E-R Diagram
Student (UCID, name, gender, degree, department)
Take (UCID, CID)
Course (CID, name, room, time, department, credits, IID)
Instructor (IID, name, gender)

29. Database Creation SQL (1)
Create table Student (
UCID varchar(20),
name varchar(100),
gender varchar(1),
degree varchar(20),
department varchar(20),
PRIMARY KEY (UCID))

30. Database Creation SQL (2)
Create table Instructor (
IID varchar(20),
name varchar(100),
gender varchar(1), PRIMARY KEY (IID))

31. Database Creation SQL (3)
Create table course (
CID varchar(20),
name varchar(100),
room varchar(1),
time varchar(20),
department varchar(20),
credit int,
IID varchar(20),
PRIMARY KEY (CID),
FOREIGN KEY (IID) REFERENCES Instructor(IID) )

32. Database Creation SQL (4)
Create table take (
UCID varchar(20),
CID varchar(100),
PRIMARY KEY (UCID, CID),
FOREIGN KEY (UCID) REFERENCES Student(UCID),
FOREIGN KEY (CID) REFERENCES Course(CID) )

33. Inserting data SQL queries
INSERT INTO Student VALUES (‘ac123’, ‘Mike Liu’, ‘M’, ‘BS’,’Management’)
INSERT INTO Instructor VALUES (‘zh5’, ‘Zhe He’, ‘M’)
INSERT INTO Course VALUES (‘CS103’, ‘Computer Science – Business Problem’, ‘MALL PC 40’, ‘TR ’,’CS’,3,’zh5’)
INSERT INTO take VALUES (‘ac123’, ‘CS103’)

34. Query examples SELECT UCID FROM students SELECT name
List all the students’ UCID
SELECT UCID
FROM students
List all the students in Architecture department
SELECT name
WHERE department = ‘Architecture’

35. Query examples SELECT S.UCID, S.name FROM Students S, Take T
List all the students who are taking CS103
SELECT S.UCID, S.name
FROM Students S, Take T
WHERE S.UCID = T.UCID AND T.CID = ‘CS103’
List all the instructors who are teaching CS courses
SELECT I.name
FROM Course C, Instructor I
WHERE C.IID = I.IID and C.department = ‘Computer Science’

36. Working with a Database
Generating reports
Printed information extracted from a database
Can calculate data
Calculate data per row
Calculate for entire table
Pictures and formatting can be included

37. Databases at Work Knowledge discovery Technique of databases
Generates questions for the database
Those you did not think to ask

38. Databases at Work Data mining Type of knowledge discovery
Searches for trends and patterns
Makes predictions on events
Supplies ideas for improving business
Teaching tip
Demonstrate this using Search for an author (Lee Cottrell works well!) and open one of the book entries. Below the description you will see several links describing suggested products. Data mining provides these links.

39. Databases at Work Internet uses Commercial websites use databases
Supply image and price information
Specialty databases exist online
Search engines track links
Teaching tip
Access a few specialty databases in class to demonstrate their power. An excellent example is terraserver.Microsoft.com.

40. Databases at Work Databases for individuals
Manage aspects of your life
Organizes hobbies for school
Microsoft Access is the most popular
Discussion point
An employer for my school suggested a way to improve student marketability. He states that he looks for the student that has gone beyond their studies at school and applied their learning to a hobby. As an example, he hires people with databases for their music or personal web sites.

41. Common Corporate DBMS Oracle Most popular enterprise-level DBMS
Very flexible storage system
Can be very complex
Platform independent
Offers a wide range of solutions

42. Common Corporate DBMS DB2 Venerable IBM database Platform independent
Only database using pure SQL
Teaching tip
Remind students that SQL stands for Structured Query Language.

43. Common Corporate DBMS Microsoft SQL Server Fastest growing DBMS
Only runs on Microsoft platforms
Eight different versions exist
Extremely scalable architecture
Software can grow with the data

44. Common Corporate DBMS MySQL Leading DBMS for Linux Very inexpensive
Features are those needed in business
Often faster than other DBMS
Platform independent
Teaching tip
An interesting article contrasting the strengths and weaknesses of these products can be found at