Developing Dynamic Web Applications with Dreamweaver

A web application is a website comprised of multiple pages, where some or all of the content is determined dynamically. This means the final content of a page isn't fixed until a visitor requests it from the web server. The content adapts based on the user's actions and requests, making these pages 'dynamic'.

Web applications serve various purposes for both site visitors and developers: * **Efficient Information Retrieval:** They enable visitors to quickly and easily find information on content-rich websites. Examples include corporate intranets and e-commerce sites. * **Data Collection and Analysis:** Web applications can collect, store, and analyze data provided by site visitors through forms. This data can be saved directly to databases, allowing for the creation of web-based reports for analysis. * **Dynamic Content Updates:** They allow for continuous updates to website content without requiring constant HTML modifications. Content providers can supply information to the web application, which then automatically updates the site.

Web applications are a combination of static and dynamic web pages. * **Static Pages:** These pages remain unchanged when a visitor requests them. The web server sends the page to the browser without any modifications. * **Dynamic Pages:** These pages are modified by the server before being sent to the browser. This modification is what makes them dynamic.

Static websites consist of HTML pages and files stored on a web server. When a visitor requests a page (by clicking a link, using a bookmark, or entering a URL), the web server retrieves the page and sends it to the browser without altering its content. The HTML code is predetermined by the designer and remains constant.

When a web server receives a request for a dynamic page, it passes the page to a special software component called an application server. The application server processes the code on the page, completes it based on the instructions, and then removes the code. The resulting static page is then sent back to the web server, which delivers it to the requesting browser. The browser receives only pure HTML.

Application servers allow access to server-side resources like databases. Dynamic pages can instruct the application server to extract data from a database and insert it into the page's HTML. This separates the design of the website from the content displayed to users. Instead of creating individual HTML files for each page, you can create templates for different types of information. Content is then uploaded to the database, and the website retrieves it in response to user requests. This allows for easy updating of information from a single source, propagating changes across the entire website. Dreamweaver can be used to design web forms for inserting, updating, or deleting data in databases. Database queries, written in SQL (Structured Query Language), are used to extract data from databases. The application server communicates with the database through a database driver, which acts as an interpreter between the server and the database. The driver executes the query and creates a recordset, which is a set of data extracted from the database. The recordset is then returned to the application server, which uses the data to complete the page.

Creating dynamic pages involves writing HTML and adding server-side scripts or tags to make the page dynamic. These languages are often embedded within the HTML code. Dreamweaver supports various server technologies and languages, including ColdFusion (CFML), Active Server Pages (ASP) with VBScript or JavaScript, and PHP. Dreamweaver provides tools to create the necessary server-side scripts or tags, and also allows for manual coding within its coding environment.

Here are some common terms related to web applications: * **Application Server:** Software that helps web servers process web pages containing server-side scripts or tags. * **Database:** A collection of data stored in tables. * **Database Driver:** Software that acts as an interpreter between a web application and a database. * **Database Management System (DBMS):** Software used to create and manipulate databases. * **Database Query:** An operation that extracts a recordset from a database, using SQL. * **Dynamic Page:** A web page customized by an application server before being sent to the browser. * **Recordset:** A set of data extracted from one or more tables in a database. * **Relational Database:** A database containing multiple tables that share data. * **Server Technology:** The technology used by an application server to modify dynamic pages at runtime. * **Static Page:** A web page that is not modified by an application server before being sent to the browser. * **Web Application:** A website containing multiple pages, where some or all of the content is determined dynamically. * **Web Server:** Software that responds to requests from web browsers by sending web pages.