ADO 2.5 continues to flesh out the original intent of ADO—to be the universal information interface. While there's plenty of bug fixes in this release, ADO also supports at least two entirely new objects—the Stream and the Record. You'll discover the Record object as soon as you slip and choose it instead of the Recordset object during statement completion time. But you'll learn.
The examples in the book are all written using ADO 2.5 on either a Windows 2000 or Windows 98 system. I don't expect them to compile or run on systems using older versions of ADO.
ADO 2.5 introduces the "Record" object, which can represent and manage things such as directories and files in a file system, and documents, folders, and messages in an e-mail system. A Record can also represent a row in a Recordset, but the Record object should not be confused with the Recordset object, as both have different methods and properties—also, some of the shared properties and methods behave differently.
The new Stream object provides the means to read, write, and manage the binary stream of bytes or text that comprises a file or message stream. Think of a Stream as an in-memory file. How many times have you had to write a block of data to disk when all you really wanted to do was hold on to it for a second or simply pass it to another component or tier?
ADO 2.5 introduces the use of Uniform Resource Locators (URLs) to name data store objects, as an alternative to using connection strings and command text. URLs can be used with the existing Connection and Recordset objects, as well as with the new Record and Stream objects.
ADO 2.5 also supports OLE DB providers that recognize their own URL schemes. For example, the OLE DB Provider for Internet Publishing, which accesses the Windows 2000 file system, recognizes the existing HTTP scheme.
ADO 2.5 introduces access to a special class of providers, called document source providers, that can be used to manage directory folders and documents. When a Record object represents a document, or a Recordset object represents a folder of documents, the document source provider populates those objects with a unique set of fields that describe the characteristics of the document. These fields constitute a resource Record or Recordset.
A number of new properties, methods, and events were added to ADO 2.5 to support the Record and Stream objects. We'll discuss the Stream object in Chapter 9. These new properties help ADO define documents and files. The methods permit you to programmatically copy, add, delete, and modify characters, files, documents, or other data from source to destination.