How to: Create an ADO Connection String

To connect to a data source, you must specify a connection string, the parameters of which might differ for each provider and data source. ADO directly supports five arguments in a connection string. Other arguments are passed to the provider that is named in the Provider argument without any processing by ADO.

Argument	Description
Provider	Specifies the name of a provider to use for the connection.
File Name	Specifies the name of a provider-specific file (for example, a persisted data source object) containing preset connection information.
URL	Specifies the connection string as an absolute URL identifying a resource, such as a file or directory.
Remote Provider	Specifies the name of a provider to use when opening a client-side connection. (Remote Data Service only.)
Remote Server	Specifies the path name of the server to use when opening a client-side connection. (Remote Data Service only.)

The following example

m_sConnStr = "Provider='SQLOLEDB';Data Source='MySqlServer';" & _ 
 "Initial Catalog='Northwind';Integrated Security='SSPI';"

The only ADO parameter supplied in this connection string was "Provider=SQLOLEDB", which indicated the Microsoft OLE DB Provider for SQL Server. Other valid parameters that can be passed in the connection string can be determined by referring to individual providers' documentation.

To open the connection, simply pass the connection string as the first argument in the Connection object's Open method:

objConn.Open m_sConnStr

It is also possible to supply much of this information by setting properties of the Connection object before opening the connection. For example, you could achieve the same effect as the connection string above by using the following code:

With objConn 
 .Provider = "SQLOLEDB" 
 .DefaultDatabase = "Northwind" 
 .Properties("Data Source") = "MySqlServer" 
 .Properties("Integrated Security") = "SSPI" 
 .Open 
End With