Database - Website Databases

Including a database for use with a web site will require that the web hosting company supports the type of database selected.

A database can be used for user login, product cataloges, image galleries, mailing lists, just about anything.

Some of the types of databases used on the web are:

SQL - Structured Query Language

SQL is a language used to access databases. It is used with relational databases to conduct queries (find information within the database based on criteria), add and delete information to the database and otherwise manage the data within the database.

MySQL

MySQL is an open source (free) relational database. Relational means that the data is stored in tables instead of in one long data file. It can be run on a Linx or Windows server. When hosting packages include MySQL they usually include PHP to with it.

MySQL Open Source Database

SQL Server

SQL Server is a Microsoft relational database suitable for large database driven web sites.

Microsoft SQL Server

Oracle

Oracle is a relational database management system.

Oracle Database Products

Microsoft Access

Access is another Microsoft relational database. It has it's limitations as to how much data it can hold. MS Access isn't used very much for web sites because usually a web site that requires a database has a lot of data to contain and process.

Microsoft Access

Client Side Scripts

Client side scripts are scripts the browser runs on the visitor's computer. There is no communication between the web server and the browser. All the script processing is done via the browser.

Client side scripts are coded directly into the HTML document or in an external file.

Client side scripts can be used to check the validity of information within forms before submitting, to write information to the web page such as the current date and time, to perform certain things when activated by the visitor such as showing and hiding page items. For more information on client side scripting and HTML visit http://www.w3.org/TR/WD-script-970314

Newer browser security features enable the visitor to disable scripting. This could be a problem if the web page relies on client side scripting to convey information such as naviagtion (e.g. cascading menus, expanding menus).

Search engines do not read scripts therefore if the navigation system on the page is not viewable without executing the script the search engine spiders will not follow the links to other pages.

Some commonly used client side scripting include:

JavaScript

Javascript was developed by Netscape and is executable in all browsers.

Please note:  Javascript and Java are not the same thing. They are completely differnt programming techniques. Javascript is compiled and executed by the browser, Java is compiled into something called Applets and inserted into the web page.

VBScript

VBScript is Mircrosoft's version of javascript. It can be inserted into a web page or used as part of an ASP page. It is proprietary coding that only works if the visitor is using Internet Explorer when inserted directly into the web page. If inserted into an ASP page script as part of the creation of the page before it is sent back to the browser then the type of browser the user is using shouldn't be a problem.

Java Applets

Java applets are small programs imbedded into the web page which are run by the browser. They are quite secure as they cannot access the user's computer and generally do not send information out to other computers.

Java applets are used for things like animation, clocks, calculator, etc.

DHTML - Dynamic HTML

DHTML uses scripts to dynamically change the content of the web page via the browser.

Some examples of DHTML would include cascading menus, items that appear and/or disappear depending on the visitors actions, sorting or filtering information received from the web server without requesting the information again from the server.

Server Side Scripts

Server side scripts, as the name suggests, run from the web server. The browser sends a request, the script is run on the server and the results are sent back to the browser.

Server side scripts can access databases and files not viewable to the visitor, process the information requested then send back a page with page containing the information requested. Examples for server side scripting would be logins (required for password protected areas of the site), returning a products page based on product type selected, processing a form submitted to the site, etc.

Server side scripting can slow down the rendering of a web page. The browser requests information, the server processes the request and returns the results. If the database and/or programming is not optimized efficently or there is a lot of data to process and return the response time is slowed down.

There various types of server side scripts available. When selecting your web hosting make sure the type of script selected is supported by the web host.

Some commonly used server side scripting programs include:

CGI - Common Gateway Interface

CGI is an interface between the server and a cgi program. It defines how data is passed from the server to the CGI program. A CGI program can be written in different programming languages.

PERL - Practical Extraction and Reporting Language

PERL is a scripting language used frequently for writing CGI applications. It is very good for manipulating data and text.

ASP - Active Server Pages

ASP pages are Microsoft technoloy based dynamic web pages. Like CGI programs, it manipulates data and text and returns the information to the browser. The pages can contain regular HTML tags and programming scripts. These type of pages have an extension of .asp attached to the file name.

PHP - PHP: Hypertext Preprocessor

PHP is an open source (free) dynamic web page programming language. The pages can contain regular HTML tags and programming scripts. It is commonly used with MySQL, an open source database. These type of pages have an extension of .php attached to the file name.