Scenario
This example illustrates how to load unique data via XPO. It is useful when your database contains a great amount of duplicated data and you need to find only unique values.
There are three approaches for this task:
XPView
Use the XPView component, add the required properties to it, and set the properties' Group attribute to True.
LINQ
Use the XPQuery<T> class to construct LINQ expressions with the Distinct method.
PersistentAlias
Use Free Joins to build criteria based on persistent objects that are not directly related.
For implementation details, see the Form1.xx and NorthwindObjects.xx files.
See also:
Querying a Data Store