class Association extends EntityNamedElement {
  ref Entity[1] sourceEntity;
  ref Entity[1] targetEntity;
  ref NavigationProperty sourceNavigation;
  ref NavigationProperty targetNavigation;
  attr String[1] sourceMultiplicity;
  attr DeleteAction sourceOnDelete;
  attr String[1] targetMultiplicity;
  attr DeleteAction targetOnDelete;
  attr String[1] associationSetName;
}

class Entity extends EntityNamedElement, ContentTableEntity {
  attr boolean ~abstract;
  attr EntityAccess access;
  attr String[1] entitySetName;

  ref Entity baseType;

  @gmf.compartment(layout="list", collapsible="true")
  val SingleProperty[*] singleProperties;

  @gmf.compartment(layout="list", collapsible="true")
  val NavigationProperty[*] navigationProperties;
}

@gmf.node(label="displayName", figure="rounded", label.icon="true", border.color="0,0,0")
class NavigationProperty extends Property {
  ref Association[1] relation;
}