ADO » Introduction
Download free PDF version
Welcome to the DevGuru ADO Quick Reference guide. This is an informative 323 page reference source that documents all of the properties, collections, methods, and events for the nine ADO (ActiveX Data Objects) objects and the three RDS (Remote Data Services) objects. Note that two new objects, Record and Stream, were added to ADO with version 2.5.
Microsoft introduced ADO to the world during the winter of 1996. From the inception, ADO was designed to be a high-level interface to provide ease of access to data stored in a wide variety of database sources. The earlier versions of ADO could only access relational databases with fixed columns and data types. However, since the release of version 2.5, ADO is now able to interface not only with relational databases, but also with non-relational databases, folders, data files, and even e-mail messages. For example, ADO can now handle data that are contained in a tree-like structure with a root, nodes, and leaves. It can also handle data where the number of columns and the data type vary from row to row. This represents a significant improvement in the usefulness and value of ADO.
The recent release of ADO 2.6 (and now 2.7) has extended this scope even farther to support the use of XML in conjunction with SQL Server 2000. This added capability allows the Stream object to contain not only an XML command that can then be executed against SQL Server 2000, but also XML data returned as a result of a query. This latest release also offers improved performance of commands that only return a single row and more detailed information to help with errors.
In ADO 2.6 and greater, the Command object has gained three new properties, CommandStream, Dialect, and NamedParameters. The Parameter and Record objects both now support a Properties Collection. Also note that the Status property is now filled with information to help with the 'Errors Occurred' error. Check it out.
The key to this newly-found versatility is the component-based technology of OLE DB. OLE DB was conceived by Microsoft as an answer to the expanding needs of the Internet and e-commerce. Microsoft has an ultimate goal of universal data access and OLE DB represents an important evolutionary step towards reaching that goal.
ADO can be used with a variety of programming languages, including Visual Basic, VBScript, JScript, Visual C++, and Visual J++. Further, by using ASP, you can reference ADO components on HTML-generated Web pages.
ADO is an important technology with which all developers should be familiar.
