12.0.0- ASP and Data Store Access

ASP and Data Store Access

We've reached an important juncture in this book. In the chapters up to and including Chapter 11, everything we've discussed and coded has involved data stored in local variables within the ASP page, or captured (for example, by an HTML form) and stored in one of the collections of the ASP Request method. These information storage techniques are excellent for the purposes of temporary data storage within an ASP page or application. But clearly, neither of these techniques is going to be suitable for storing large amounts of information, or for storing data indefinitely. Therefore, we need to look to other data storage methods.

Many companies use databases of one sort or another to store the data required in the creation of their web pages, and also to store data that is entered by the end-users and captured by the web pages. But it goes further than databases – there aren't many of us who store all of our data on databases. Most companies have data sources of many other formats, such as mail systems, legacy mainframes, spreadsheets and word-processed text files. Data stored in these formats might also benefit from being published on the web – and so we'd like to be able to extend database access techniques to these other forms of data.

Until recently, the idea of having a common method of data access – which could access the data held in all these diverse applications and formats – was a far off dream. Microsoft uses the term Universal Data Access (UDA) to refer to their strategy for dealing with this problem. As part of its UDA strategy, Microsoft developed a technology known as OLE-DB, which has brought this dream much closer to reality.

Moreover, this dream affects ASP – because we can use OLE-DB in ASP, via a set of programming interfaces known as the ActiveX Data Objects, or ADO. Through the WWW, intranets and other browser-based applications, the humble Web browser is becoming one of the most widely-used interfaces between data and end-user.

The first 11 chapters of this book have demonstrated how to put active scripting into our ASP pages; in the next few chapters, we'll look at how we can use this scripting capability to access data stores and populate our pages dynamically with the most current, up-to-date information. This is the real significance of the word 'Active' when we talk about 'Active Server Pages'. In this chapter, we will begin our study of data access by concentrating on the data store and how to connect to one. So we are going to look at:

• What we mean by a data store
• What ODBC is
• What OLE-DB is
• How ADO fits in
• Exactly what a database connection is
• How to use the ADO Connection object