Terms, definitions, and abbreviated terms

3.1 Terms and definitions

attribute

unit of information within an entity, defined by a particular type or reference to a particular entity NOTE There are three kinds of attributes: direct attributes, inverse attributes and derived attributes.

direct attribute

inverse attribute

unit of information defining queries for obtaining related data and enforcing referential integrity NOTE Similar to the term "navigation property" in entity-relational programming frameworks.

derived attribute

unit of information computed from other attributes using an expression defined in the schema

constraints on attributes

data type restricting the values of attributes NOTE The most general constraint is about the existence of attribute values. There are basically two types: mandatory and optional attributes. Values of mandatory attributes must be provided whereas values of optional attributes may be omitted. NOTE For aggregation data types such as Set, List, or Array, the existence constraint is often refined by a minimal and maximal number of elements, which is also known as cardinality.

entity

class of information defined by common attributes and constraints as defined in [ISO 10303-11] NOTE Similar to the term "class" in common programming languages but describing data structure only (not behavior such as methods).

identification

capability to find, retrieve, report, change, or delete specific instances without ambiguity

instance

occurrence of an entity NOTE Similar to the term "instance of a class" in object oriented programming.

object

anything perceivable or conceivable that has a distinct existence, albeit not material

type

basic information construct derived from a primitive, an enumeration, or a select of entities NOTE Similar to the "Type" construct as defined in [ISO 10303-11]. NOTE Similar in concept to "typedef" or "value type" in common programming languages.

select

construct that allows an attribute value to be one of multiple types or entities NOTE Similar to the "Select" construct as defined in [ISO 10303-11]. NOTE Similar to a "marker interface" in common programming languages.

enumeration

construct that allows an attribute value to be one of multiple predefined values identified by name NOTE Similar to the "Enumeration" construct as defined in [ISO 10303-11]. NOTE Similar in concept to "enum" in common programming languages.

actor

person, an organization, or person acting on behalf of an organization NOTE A specialization of the general term object.

classifcation

categorization, the act of distributing things into classes or categories of the same type

constraint

restriction for a specified reason NOTE A specialization of the general term control.

control

directive to meet specified requirements such as for scope, time, and/or cost NOTE A specialization of the general term object.

dictionary

collection of words, terms or concepts, with their definition

element

tangible physical product that can be described by its shape representation, material representations, and other properties NOTE A specialization of the general term product.

element occurrence

element's position within the project coordinate system and its containment within the spatial structure

external reference

link to information outside the data set, with direct relevance to the specific information the link originates from inside the data set

feature

parametric information and additional property information modifiying the shape representation of an element to which it applies

group

collection of information that fulfills a specified purpose NOTE A specialization of the general term object.

library

catalogue, database or holder of data, that is relevant to information in the data set NOTE It is information referenced from an external source that is not copied into the data set.

object occurrence

characteristics of an object as an individual NOTE Similar to "object", "instance", "individual" in other publications.

object type

common characteristics shared by multiple object-occurrences NOTE Similar to "class", "template", "type" in other publications.

process

object-occurrence located in time, indicating "when"

property occurrence

unit of information providing a value for a property identified by name

property template

metadata for a property including name, description, and data type NOTE Similar in concept to "extension property" in common programming languages.

property set occurrence

unit of information containing a set of property occurrences, each having a unique name within the property set

property set template

set of property templates serving a common purpose and having applicability to objects of a particular entity NOTE Similar in concept to "extension class" in common programming languages.

proxy

object that does not hold a specific object type information NOTE a specialization of object occurrence.

quantity

measurement of a scope-based metric, specifically length, area, volume, weight, count, or time

relationship

unit of information describing an interaction between items

representation

unit of information describing how an object is displayed, such as physical shape or topology

resource

entity with limited availability such as materials, labor, or equipment NOTE a specialization of the general term object. NOTE the "resource definition data schemas" section is unrelated to this concept.

space

area or volume bounded actually or theoretically NOTE a specialization of the general term product.

3.2 Abbreviated terms