ADO

Vo2Ado uses Microsofts Active Data Objects technology (ADO), a rich hierarchy of OLE classes that Microsoft supplies for interfacing with OleDb Datasources on 32-bit platforms.

Before using Vo2Ado, you must ensure that a copy of ADO (version 2.1 or higher) is installed on your computer. ADO may already be installed if you are using Internet Explorer, Microsoft Office 2000 or are running on a Windows 98 machine.

If you don't have ADO installed, you can download it from the Microsoft Website at: http://www.microsoft.com/data

ADOX

Vo2Ado also uses ADOX, an extension to ADO that allows developers to programmatically create and maintain database structures. At this moment only the prociders for the Microsoft Jet Engine and Microsoft SQLServer support this interface, but more providers are expected to support this interface in the future.

Applications can communicate with the Ado OLE objects using two kinds of interfaces:

An OLE Automation interface for use with OLE automation clients such as Visual basic, Visual Objects and other development languages. This interface is easy to use, but not so very fast. The reason this interface is not very fast is because it is late bound, and all arguments are passed as variants (the OLE equivalent of the VO Usual data type). At run time when you call a method the method name must be looked up and the arguments must be converted from their VO data type into variants and back to the data types that Ado needs on the other side.

When you generate classes using the Ole Automation Server wizard inside VO, part of this speed problem is resolved, because method names are converted to their numeric identifiers, but still the conversion of the data types is necessary.

A COM interface designed for use with compiled languages such as Visual C++ and Visual Objects, where speed is very important. With these interfaces all COM calls are early bound, and the arguments to the methods are passed in the data type that the Ado classes expect, so no extra conversion is necessary.

For speed reasons Vo2Ado uses the COM interface in stead of the slower OLE Automation interface. The performance of the classes is this way 5 to 10 times faster than using OLE Automation.

Support

When you need support for using Vo2Ado you can get that through the following ways:

•Get in contact with your dealer

•Send an e-mail message to support@heliks.nl

•Post a message in the Usenet newsgroup comp.lang.clipper.visual-objects

Updates and patches

For new updates and patches look at: http://www.heliks.nl