|  | | | Chapter 1 - Displaying Data on the Web | | | byJohn Kauffman, Fabio Claudio Ferracchiatiet al.? | | | Wrox Press ?2002 | | | | | Some of the advantages of having a data-driven system are immediately apparent, but there are others that are less tangible and not so readily evident. Naturally enough, there are also reasons why you might not want to attach a web site to a database. In this section, we'll examine the benefits and the drawbacks of creating a web site that's based around a data source. Advantages There are many secondary benefits of making a web site data-driven, such as the ability to reuse portions of functionality in other projects, and being able to share common pieces of information across systems - these tend to kick in when you start to work on your second or your third web application. Here, we're going to look at some of the advantages that can start to accrue as soon as you make the decision to create a data-driven site: -
Quality and timeliness of content. The most immediate advantages to making a site data-driven are the speed with which new information can be presented on the Web, and the controls that can be put in place to guarantee the quality of this information. Rather than having to get a web designer to create a page containing the information, and then get it uploaded again every time a price changes or a new product is added, a tool can be created that enables the instant publishing of new or updated information simply by modifying the database. This is one of the key benefits of the Web over traditional media - the ability to view information in real time, rather seeing than a snapshot of old data. By enforcing rules on who can add and amend data, how it is checked, and whether it is approved, data can be verified prior to being published in a much more rigorous manner, ensuring that the user only sees accurate details. -
Functionality. The other main benefit of storing all of the data required for a site in a database is that of improved functionality in terms of the actions that the user can perform on the system. Rather than producing 'catalogues', which (like this book) just have an index and a contents table as a means of searching, forms can be created that allow the user to specify what is being looked for, and have the system scour the database for that information. A great example of this is a search engine. Without a database, such a site would present only a manual categorization of other web sites, with a huge structure of pages that you could (try to) navigate between. -
Maintenance. With the data for a site stored in a separate location from the presentation code, there is no longer a need to maintain static links in HTML files between related sections of a site, forcing you to reapply formatting and menu structures to hundreds of pages each time the site is redesigned. In a data-driven system, web pages are typically templates that act for entire classes of pages, rather than having one page for each piece of information. As an example of this, you could imagine the on-screen appearance of a page that displays the details of a product for sale. Rather than this being a separate HTML page, in a data-driven system there would be one page containing fields and tables that could be populated with data regarding any product. This means that there is far less to do each time a redesign is implemented. Similarly, as the relationship between different pieces of information can be stored in the database (rather than hard-coded in the pages), links to related products and other information can be generated on the fly. Disadvantages Although there are many advantages to making a web site data-driven, some of them come at a price, and a data-driven site is not always the right solution to your problem. There are several hurdles that must be overcome in order to provide a richer experience to the end user, and it's important that you consider them before taking the plunge: -
Development. A large number of web sites that are now data-driven started out being static, and there are still many static sites being created to this day. The nature of the content you want to . present is not always suited to a data-driven site, and the creation of a data-driven system requires extra time and skills, resulting in a product that is more complex, and (inevitably) more prone to errors. These costs have to be weighed up against the advantages that such a system provides. -
Performance. The performance of data-driven web sites is an issue that crops up regularly. If a site is entirely static, then there are no constraints on the way the system is organized, or on how it can expand to cater for higher volumes of users. The simplest way to increase performance is to buy a faster processor and more memory. When that stops being viable, multiple versions of the site can be created, and users redirected to whichever one is under least load. This can continue in a linear fashion, with the same increase in performance each time a new web server is added. With a data-driven site, this is not the case, because the entire system is dependent upon one resource: the database. If it's not carefully designed, the database can create a bottleneck in the system, whereby the rest of the application is held up while it waits for information to be retrieved. Removing this bottleneck is a difficult problem to solve - having multiple synchronized databases is one of the few real solutions, but it can prove very expensive, and the overheads involved in this synchronization are significant. -
Cost. In addition to the technical considerations mentioned above, there are also associated commercial issues. For a relatively static site, the time required to create a database and write the code to access it may be longer than it would take just to edit some HTML pages. Also, enterprise-class database systems are themselves expensive. Considering Microsoft's data storage solutions alone, it's well known that producing a solution using SQL Server (Microsoft's enterprise-level database server) provides many benefits over Access (its desktop database), such as higher performance and better support for industry standards, but comes with a price tag to match. |
