concept "monthly net income of person" may thus have one data element called "monthly net income of individual by 100 dollar groupings" and one called "monthly net income of person range 0-1000 dollars", etc., depending on the heterogeneity of representation that exists within the data holdings covered by one ISO/IEC 11179 registry. Note that these two examples have different terms for the object class (person/individual) and different value sets (a 0-1000 dollar range as opposed to 100 dollar groupings). The result of this is a catalogue of sorts, in which related data element concepts are grouped by a high-level concept and an object class, and data elements grouped by a shared data element concept. Strictly speaking, this is not a hierarchy, even if it resembles one. ISO/IEC 11179 proper does not describe data as it is actually stored. It does not refer to the description of physical files, tables and columns. The ISO/IEC 11179 constructs are "semantic" as opposed to "physical" or "technical". The standard has two main purposes: definition and exchange. The core object is the data element concept, since it defines a concept and, ideally, describes data independent of its representation in any one system, table, column or organisation. Structure of the ISO/IEC 11179 standard The standard consists of seven parts: ISO/IEC 11179-1:2015 Framework (referred to as ISO/IEC 11179-1) ISO/IEC 11179-2:2005 Classification ISO/IEC 11179-3:2013 Registry metamodel and basic attributes ISO/IEC 11179-4:2004 Formulation of data definitions ISO/IEC 11179-5:2015 Naming and identification principles ISO/IEC 11179-6:2015 Registration ISO/IEC 11179-7:2019 Metamodel for data set registration Part 1 explains the purpose of each part. Part 3 specifies the metamodel that defines the registry. Part 7 is released per December 2019 and provides an extension to part 3 for registration of metadata about data sets. The other parts specify various aspects of the use of the registry. Overview of 11179 Data Element The data element is foundational concept in an ISO/IEC 11179 metadata registry. The purpose of the registry is to maintain a semantically precise structure of data elements. Each Data element in an ISO/IEC 11179 metadata registry: should be registered according to the Registration guidelines (11179-6) will be uniquely identified within the register (11179-5) should be named according to Naming and Identification Principles (11179-5) See data element name should be defined by the Formulation of Data Definitions rules (11179-4) See data element definition and may be classified in a Classification Scheme (11179-2) See