Named attributes

A named attribute is an atomic attribute that is defined in the query language. It can be either an object (for example, item) or a terminal (for example, pk).

The query language defines 11 named object attributes:
  • item
  • category, location, parent, child
  • spec
  • step
  • catalog, hierarchy
  • log, logentry
The query language defines different sets of named terminal attributes for each of the object attributes or object types:
  • item: pk
  • category: pk, path, level
  • parent: pk, path, level
  • child: pk, path, level
  • location: pk, path, level
  • spec: name, type, attribute_path
  • step: path, reserved_by
  • catalog: name
  • hierarchy: name
  • logentry: log, message, timestamp
You can access named attributes in an object by using dot notation. In the following examples, the first one accesses the pk attribute in the item; the second one accesses the level attribute in the category; and third one accesses the catalog attribute in the item and then accesses the name attribute in the catalog.
  1. item.pk
  2. category.level
  3. item.catalog.name