Validating Dictionary Types 
When data objects are imported, corresponding data dictionary types are created. These dictionary types are simple or built-in types. You can perform type validations on these dictionary types. Before persisting a data object attribute, the data dictionary validation takes place at the service component level.
For example, there is an error in the value entered for the Age attribute. When you try to save this value, validation takes place at the service component level, which identifies the value as incorrect. This causes an exception to be raised and is propagated to the UI component level.
For more information about Java dictionary data types, see: Providing Java Dictionary Tables and Data Types
You have created a data object.
More information: Creating Data Objects
You have created a service component and defined its dependencies.
More information:
In the Service Explorer, expand the Data Objects node.
Select the data object.
Navigate to the Attributes tab page.
If the attribute value has to be validated for the correct data type, select Yes in the Type Validation field.