ADO: ActiveX Data Objects

Configuring Connections

Let’s now take a look at the different ways in which we can configure the connection to a data source through the use of a Connection object. In this section, I will explain how to work with connection strings and Data Source Names (DSNs). Connection strings are detailed explanations of how to open a data source, while Data Source Names are just a name of a definition that is stored on the current machine, by the operating system rather than the application. In addition, I will also talk about how to obtain the version number for the ADO library that you are using and how to set connection options such as the cursor location (whether to run the cursor on the server or the client), the default database setting, and the permission settings.

Working with Connection Strings

All connections revolve around connection strings, which contain all the pertinent information to ADO concerning the establishment of a connection to our data source. The connection string comprises a number of arguments. There are five standard ADO arguments that can be used in a connection string:

Provider

Identifies the name of the data provider that you wish to use to establish a connection to a data source. The data provider indicates the type of data source. The Provider argument can be set to such things as Microsoft’s OLE DB provider for SQL Server (SQLOLEDB.1) or Microsoft’s OLE DB provider for Jet (Microsoft.Jet.OLEDB.4.0). (I will talk about the various types of data providers later ...