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When your web site needs to collect, store and act dynamically on information, that usually means you will need some custom programming done and probably a database. Web-based databases are very similar to traditional databases. They have data-entry screens, reports and some sort of internal storage mechanism.
Web-based databases are different from those on your desktop in a few ways. The most important difference is that they usually require a higher level of custom programming to make them work. While there are tools, such as Macromedia's Dreamweaver MX, that make it easier, most fancy databases require a programmer to make them work well.
It is often difficult to determine when your web site will need a database and when it won't. Here are a few examples of on-line applications that require Web-based databases:
- A searchable directory of consultants
- A discussion board to exchange ideas about a particular topic
- An on-line donation system
- An on-line store or auction
- A membership system for a Web site
- A "Members only" section of your Web site
- Nearly anything you can imagine!
Lets look at an example, a searchable directory of consultants. To see it in action, visit the Nonprofit Management Fund's Technical Assistance Directory. This is a classic example of a Web-based database.
Now, web pages can either be plain-old documents, like this one, or they can have functionality.
If the TA Directory was just a giant list without a database you would lose the following functions:
- You couldn't really search. It would be more like "scrolling"
- You couldn't have people submit their own information. You would have to collect it and then edit the document yourself.
- You couldn't sort the information by "Areas of Expertise" or any other attribute, for that matter.
Using a database, the TA Directory allows all the usual benefits that come along with databases. Those benefits include:
- Searching and sorting by different parameters
- The ability to change based on user input
- The ability to collect a lot of information without your intervention.
- Instant updating. That is, once something is in the database, it is on the Web site.
How Web-based Databases Work
Server-side scripting languages are just like other programming languages in that they describe the steps the computer must take to perform the requested action. People go to a lot of school for this stuff, so rates are usually in the $90-125/hour range for custom development. They are a required interface between the database and the final HTML page.
Nearly any data-driven web page involves 3 of these programming languages:
- HTML : Hypertext Markup Language. This is what started the whole World-wide web, despite what Al Gore has told people.
- A server-side scripting language. This can be PHP, Perl, ASP, ColdFusion, Lasso or any other such language.
- SQL: Structured Query Language. This is the universal language of databases. This is how reports are created and data is selected based on different statements in SQL.
So, how do these pages know what you want? Well, let's use the example of an internet search. You usually type some search text into a form like this one:
Search:
You'll notice that when you press search buttons you go to a different page and the address bar looks a bit jumbled:
Let's look at what happened. In this example, I searched for "Hardware" in our Web.dots link directory. In the resulting page, my "Hardware" text is now in the address bar. Hmmm.
In the below image, details.php, highlighted in red, is a dynamic page complete with server-side scripting and sql. This single page is capable of displaying anything related to whatever text is assiged to the "category" paramenter, highlighted in blue.
If you're curious, you can try manually editing the url parameters you see while browsing the Web. Some of them are intelligable like this one while others are encoded for security purposes.
Now that you know a bit about Web-based databases, try looking at a few examples to see the virtually endless possibilities.
Examples of Web-based Databases
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