From Xojo Documentation
Optional attribute. This property is used in conjunction with the Attribute property to set a string property using the SQLSetConnectAttr ODBC API function.
Using the Attribute property, the attribute is only set before the connection is made to the database. Although the Attribute / AttributeString properties are readable, they are not updated with information from the database.
The AttributeString property is not passed to the database if the Attribute property is set to zero (the default).
For more information, see the documentation for the SQLSetConnectAttr function at msdn.microsoft.com.
If you don't want to pass AttributeString, pass the empty string.
The following code sets the SQL_CURRENT_QUALIFIER property:
db.AttributeString = "NorthWind"