XML Is a Long-Term Solution

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In the long run, you would do well to make Extensible Markup Language (XML) your standard for data abstraction and for data transport. ADO 2.5, which ships with Windows 2000 and which is also available for download if you're a late adopter of Windows 2000, has very good support for XML. It easily generates XML documents from simple or hierarchical recordsets, and it just as easily regenerates XML documents into updatable ADO recordsets.

There are many reasons for you to embrace XML. You'll find heaps of reasons in a multitude of books and articles all over the place, and we have no wish to add to that. And yet, we'll tell you this:

• XML is an official World Wide Web standard, whereas ADO is and will continue to be a Microsoft standard.
• Because XML is an official Web standard, it will help you integrate your Microsoft applications with other applications in ways that ADO will never come close to. Browsers from different vendors will have to support XML according to the standard, which means that you'll be able to send even complicated state to the client rather than keep it in the server for the sake of the client. Therefore, XML will provide a huge advantage in e-commerce applications. Using XML, your company will also be able to send validated business documents to other companies, and those companies will be able to receive them and handle them, even if they have an entirely different computing platform than your company does.
• XML is inherently hierarchical. ADO is not. In ADO, hierarchy is an afterthought, and that's evident when you take a look at its shortcomings in this respect, as described earlier in this chapter and at length in Chapter 19.
• The Document Object Model (DOM) boosts the value of XML by making your XML data sets available for your application code. Without the DOM, XML would have a weak spot in comparison with ADO since ADO has always been open to manipulation with application code. With the DOM, there is no such weak spot in XML.
• Windows 2000 features version 2.5 of ADO. This new version has functions to convert ADO recordsets to XML data sets and then back again. In our opinion, through ADO 2.5, Windows 2000 creates the necessary conditions for the developer's productive use of XML.

Throughout this book, and especially in Chapter 9, "Using Separate COM Interfaces," and Chapter 20, "An XML Overview," you'll see examples of how XML can be used as a replacement for the ADO recordsets used before the advent of Windows 2000.