1. Database Management Systems
Chapter 05
Database Management Systems

2. Database Management Systems
Database management system (DBMS)
computer software designed for the purpose of managing databases based
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
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

6. The Database Records One full set of fields Often called a row
Phone book example
Smith, Joe, 123 Some Street,
Databases may have unlimited rows

7. The Database Tables One complete collection of records
Databases may have thousands of tables

8. Database Helper Documents
Forms
Present one record to the user
Often used to change or view data
Teaching tip
Figure 11A.3 on page 423 provides examples of forms and reports.

9. Database Helper Documents
Reports
Produce printed results from the database
Includes tools to summarize data

10. 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

11. 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.

12. ER Diagram

13. 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.

14. 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

15. 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.

16. 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

17. 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

18. 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.

19. 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.

20. 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

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

22. 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

23. Survey of Database Systems

24. Enterprise Software Enterprise definitions
Systems throughout the entire organization
Very large scale computer systems
Historically found on mainframes
Modern enterprise runs on PC servers

25. Enterprise Software Suite of programs
Handles thousands of users at once
Access to millions of records
Looks and acts like a DBMS

26. Enterprise Software Distributed applications
Software installed on several machines
Data stored on several machines
Data placed closest to appropriate users
Work load is balanced among machines
Teaching tip
An example is very appropriate at this point. A good example is a sales company. There are two divisions: sales and warehousing. The enterprise application allows sales people to see inventory levels. The application is distributed. The inventory levels are stored on servers in the warehouse. The customer and order information are stored on servers in the sales division

27. Enterprise Software Tiers Software between user and data
Tiers control one part of enterprise
Two tier systems
Data storage
Client interface
Three tier systems
Add calculation
There is no limit to the tiers

28. Enterprise Software Meet the needs of many users
Applications are very complex
Support many types of users
Supports many different nationalities
Must support large data flow

29. Enterprise Software Electronic document management EDM
Tracks and organizes documents
Collaboration between team members
Database tracks all changes

30. Enterprise Software Disconnected databases
Connections are given a copy of data
Reduces the number of open connections
Reduces the data flow needs
May result in different versions of data
Teaching tip
You can demonstrate disconnected databases in action. Have your entire class access Walk through the wizard with the computer models in your classroom. Most likely, your students will have several different prices for the same product. More information on disconnected databases can be found at

31. Databases at Work Required in nearly every business Can automate tasks
Increases business efficiency

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

33. 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.

34. 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.

35. 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.

36. 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

37. 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.

38. 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

39. 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

40. End of Chapter