IndexDefinition :: hasKey - Does index provide a key definition
The property returns, whether the index provides a key definition or not. Since requesting the key definition from an index definition will throw an exception, when the index does not have got a key definition, the function can be called before requesting a key definition in order to avoid unnecessary exceptions.
... fragment ( property &person ) {
IndexDefinition id(person.propertyDefinition().indexDefinition(0));
if ( id.hasKey() )
Application::output(id.keyDefinition().name);
else
Application::output("person collection is not ordered");
}
Return value: Success ( bool )
The value is true when the function was executed successfully. Otherwise the value is set to false.