1. Week 7 Lecture Web Database Development Samuel Conn, Asst. Professor
Professor’s Notes In this lecture you will study how databases can be used on the world wide web. Implementation of database applications on the Internet is proliferating at an amazing rate, and the need for Internet database administration continues to grow. The lecture covers the basics of web database development.
Samuel Conn, Asst. Professor

2. In this lecture, you will learn:
How Internet databases are typically used
About the architecture of Web-to-database middleware
How Web-to-database middleware is used to integrate databases with the Internet
What special considerations govern Web database development 2
In this lecture, you will learn:
How Internet databases are typically used
About the architecture of Web-to-database middleware
How Web-to-database middleware is used to integrate databases with the Internet
What special considerations govern Web database development
Here are the key points to be covered in this lecture. You will study how Internet databases are used, the middleware architecture used to implement databases on the web, and the special considerations that are associated with web database development. 2

3. Web Database Connectivity
Allows rapid response to competitive pressures
New services
New products
Customer support enhanced
Fast effective information dissemination
Universal access
Local
Around the globe 3
Web Database Connectivity
Allows rapid response to competitive pressures
New services
New products
Customer support enhanced
Fast effective information dissemination
Universal access
Local
Around the globe
Connecting your businesses database to the web can offer several advantages. New services and products can be quickly introduced to the marketplace. Customer support can be enhanced and Customer Relationship Management (CRM) applications can be used. It is also a great way to deliver information around the world. 3

4. Typical Uses of Internet4
Typical Uses of Internet
Table 15.2
Here are some of the typical uses of the Internet in the facilitation of business processes……
Table 15.2 4

5. Characteristics/Benefits of Internet Technology
Hardware & software independence
Cost savings
Uses existing equipment
Platform independence and portability
No need for multiple platform development
Common simple user interface
Reduced training
Reduced support 5
Characteristics/Benefits of Internet Technology
Hardware & software independence
Cost savings
Uses existing equipment
Platform independence and portability
No need for multiple platform development
Common simple user interface
Reduced training
Reduced support
Internet technology has several benefits and distinguishing characteristics. It is independent of hardware and software that currently exists in the business enterprise. You can use existing equipment and develop into the Internet as an extension of your existing platform. The user interface is essentially thin client technology, and requires no special support or training. 5

6. Characteristics/Benefits of Internet Technology (con’t.)
Location Independence
Global access through Internet
Reduced costs for dedicated connections
Rapid development at manageable costs
Development tools
Low entry costs
Available software & access tools 6
Characteristics/Benefits of Internet Technology (con’t.)
Location Independence
Global access through Internet
Reduced costs for dedicated connections
Rapid development at manageable costs
Development tools
Low entry costs
Available software & access tools
You can have locations around the globe, so geographic location is not a barrier. And you can develop and implement on the web very quickly and with relatively low cost. 6

7. Web-to-Database Middleware
Server-side extension
Interacts directly with Web server
Handles specific requests
Also known as Web-to-database middleware
Examples
ColdFusion
CGI
API 7
Web-to-Database Middleware
Server-side extension
Interacts directly with Web server
Handles specific requests
Also known as Web-to-database middleware
Examples
ColdFusion
CGI
API
The extension of an existing infrastructure to the web is a “server-side” extension done through the use of certain software, called middleware, that creates the interface between the web access and the local database application. 7

8. Web-to-Database Middleware8
Web-to-Database Middleware
Figure 15.1
Here is a good illustration of how middleware is used to interface a backend database application with users around the world coming in through the Internet.
Figure 15.1 8

9. Web Server Interfaces Common Gateway Interface (CGI)
Uses script files to connect to database
Perl, C++, VB
Application Programming Interface (API)
Newer and more efficient
Uses DLLs
Memory resident and faster
Well known APIs
Netscape (NSAPI)
Internet Server API from Microsoft (ISAPI)
WebSite API from O’Reilly (WSAPI) 9
Web Server Interfaces
Common Gateway Interface (CGI)
Uses script files to connect to database
Perl, C++, VB
Application Programming Interface (API)
Newer and more efficient
Uses DLLs
Memory resident and faster
Well known APIs
Netscape (NSAPI)
Internet Server API from Microsoft (ISAPI)
WebSite API from O’Reilly (WSAPI)
Some of the common, but older, methods of interfacing applications to the web are technologies known as Common Gateway Interface, or CGI. CGI uses some type of programming script language, usually Perl, C++, or Visual Basic to connect to the database from the web. New technologies create an Application Programming Interface, or API, that is more efficient and faster. 9

10. API and CGI Web Server Interfaces10
API and CGI Web Server Interfaces
Figure 15.2
Here is an illustration that shows how both APIs and CGI interfaces can connect the web user to a database application.
Figure 15.2 10

11. Web-to-Database Middleware Connection Methods
Native SQL access middleware
Use services of Open Database Connectivity (ODBC) Use Object Linking and Embedding Database (OLE DB) interface with Windows
ODBC most common 11
Web-to-Database Middleware Connection Methods
Native SQL access middleware
Use services of Open Database Connectivity (ODBC) Use Object Linking and Embedding Database (OLE DB) interface with Windows ODBC most common
Connecting from the web to the database via some middleware can use various access methods, or technologies. Some middleware uses SQL in its native format to access the database. Open Database Connectivity, or ODBC, is a Microsoft “defacto” standard, which is essentially a SQL API. It is the most common form of connecting an application to a data source. 11

12. ODBC to Access Databases12
ODBC to Access Databases
Figure 15.3
Many third party application development tools use ODBC as the way to access the database.
Figure 15.3 12

13. Web-to-Database Middleware Uses ODBC to Access Databases13
Web-to-Database Middleware Uses ODBC to Access Databases
Figure 15.4
Here is a good illustration of how an application would use ODBC technology to interface the application with the relational database, and connect to the data source.
Figure 15.4 13

14. Web Browser Located on the client computer End user Web interface
Interprets HTML code received from Web server
Presents page components in a standard way
Client-side extensions
Plug-ins
Java and JavaScript
ActiveX and VBScript 14
Web Browser
Located on the client computer
End user Web interface
Interprets HTML code received from Web server
Presents page components in a standard way
Client-side extensions
Plug-ins
Java and JavaScript
ActiveX and VBScript
The web browser is essentially the “client” where the user interface runs. The browser interprets HTML code and presents it in a format that the user can read. There are “extensions” on the client-side, referred to as plug-ins, script, or controls, that allow enhancements at the presentation layer to the user. 14

15. The Web as a Stateless System
Web server does not know status of any client at any given time
Request-reply model of communication
Browser concerned only with current page
Data processing requires additional software
Java, JavaScript, VBScript 15
The Web as a Stateless System
Web server does not know status of any client at any given time
Request-reply model of communication
Browser concerned only with current page
Data processing requires additional software
Java, JavaScript, VBScript
The web is considered to be “stateless”, meaning that it does not know the status of any client at any given time. Clients simply initiate “requests” that are processed by the server-side, and the a “reply” is sent back to the client. Browsers are the ultimate “thin client” in that they have minimal resources, are only concerned with presentation of the current page, and require additional technology to achieve any kind of processing. 15

16. Internet Database: Special Considerations
Involve more than just database-enabled Web applications
Issues important to corporate databases
Data security
Transaction management
Client-side data validation
Operational and management challenges
Database applications development most affected by Internet 16
Internet Database: Special Considerations
Involve more than just database-enabled Web applications
Issues important to corporate databases
Data security
Transaction management
Client-side data validation
Operational and management challenges
Database applications development most affected by Internet
Some of the special considerations with Internet database design are data security, transaction management, client-side data validation, and some operational/management issues. Since the interface works differently than a standard client/server implementation, database engineers must work closely with network engineers to address certain issues of special concern to Internet database applications. 16

17. Supported Data Types Integrated data from multiple sources
Word-processor documents
Pictures
Sounds
Movies
Methods for storing and extracting data objects
Overhead created by storage
Client browser support of object being accessed
Size of database considering multimedia and other data 17
Supported Data Types
Integrated data from multiple sources
Word-processor documents
Pictures
Sounds
Movies
Methods for storing and extracting data objects
Overhead created by storage
Client browser support of object being accessed
Size of database considering multimedia and other data
The Internet database applications support a full range of data types across the Internet. Working with large files from multimedia data types generally has more issue with availability of bandwidth, than from any database management issues. 17

18. Data Security Web Server Level RMDBS Vendors
Secure transactions using encryption
TCP/IP protocol level
Firewalls
RMDBS Vendors
Login authentication
Restrict access to particular SQL commands
Web-to-database middleware
End user restrictions
Designer created algorithms
Must support e-commerce applications 18
Data Security
Web Server Level
Secure transactions using encryption
TCP/IP protocol level
Firewalls
RMDBS Vendors
Login authentication
Restrict access to particular SQL commands
Web-to-database middleware
End user restrictions
Designer created algorithms
Must support e-commerce applications
Data security is a big issue on the Internet. With the potential for data security to be violated many times higher because of the general access to the Internet, many ecommerce applications work with both database security and network security as an integrated policy of how to protect data coming across the Internet. 18

19. Transaction Management
Concept is foreign to Web
Dilemma created by request-reply model
Web cannot maintain open line between client and database
Recovery requires client maintain open communications
Designers must ensure proper transaction management support at database server level 19
Transaction Management
Concept is foreign to Web
Dilemma created by request-reply model
Web cannot maintain open line between client and database
Recovery requires client maintain open communications
Designers must ensure proper transaction management support at database server level
Transaction management is a little different across the Internet because of the lack of a persistent connection between the database and the application. Transaction management must be supported at the database server level. 19

20. Denormalization Web forms Solutions
Cannot use multiple data entry lines
1:M relationships problematic
Solutions
Web programming languages
Java, JavaScript, VBScript 20
Denormalization
Web forms
Cannot use multiple data entry lines
1:M relationships problematic
Solutions
Web programming languages
Java, JavaScript, VBScript
Sometimes database applications must “denormalize” data to get associated data into one table so that web forms can be developed to access the data. Fortunately, there are solutions to these kinds of problems through the use of various web programming languages. 20