Unit

Generalization is AnnotatedIdentifiable.

Superclass hierarchy

Definition

Individual object of interest for some statistical activity, such as data collection

Examples

Here are 3 examples - 1. Individual US person (i.e., Arofan Gregory, Dan Gillman, Barack Obama, etc.) 2. Individual US computer companies (i.e., Microsoft, Apple, IBM, etc.) 3. Individual US universities (i.e., Johns Hopkins, University of Maryland, Yale, etc.) [GSIM 1.1].

Explanatory notes

In a traditional data table each column might represent some variable (measurement). Each row would represent the entity (Unit) to which those variables relate. Height measurements might be made on persons (UnitType) of primary school age (Universe) at Pinckney Elementary School on September 1, 2005 (Population). The height for Mary Roe (Unit) might be 139 cm.

The Unit is not invariably tied to some value. A median income might be calculated for a block in the U.S. but then used as an attribute of a person residing on that block. For the initial measurement the Unit was the block. In the reuse the unit would be that specific person to which the value was applied.

In a big data table each row represents a unit/variable double. Together a unit identifier and a variable identifier define the key. And for each key there is just one value – the measure of the unit on the variable.

A big data table is sometimes referred to as a column-oriented data store whereas a traditional database is sometimes referred to as a row-oriented data store. The unit plays an identifier role in both types of data stores.


Subclasses


Properties

Name

Description

Data Type

Multi- plicity

definition
from Unit

Natural language statement conveying the meaning of a concept, differentiating it from other concepts. Supports the use of multiple languages and structured text.

InternationalStructuredString

0..1

displayLabel
from Unit

A structured display label providing a fully human readable display for the identification of the object. Supports the use of multiple languages and structured text.

LabelForDisplay

0..*

name
from Unit

A linguistic signifier. Human understandable name (word, phrase, or mnemonic) that reflects the ISO/IEC 11179-5 naming principles. If more than one name is provided provide a context to differentiate usage.

ObjectName

0..*

Inherited Properties

Name

Description

Data Type

Multi- plicity

agency

Agency expressed as filed with the DDI Agency ID registry [registry.ddialliance.org] with optional additional sub-agency extensions.

:ref:``

1..1

id

ID conforming to the allowed structure of the DDI Identifier and must be unique within the Agency.

:ref:``

1..1

isPersistent

Default value is false indicating that the content of the current version may change (may be in development mode). Set to true when the content of this version will no longer change.

:ref:``

1..1

isUniversallyUnique

Default value is false. If the id of the object was created as a Universally Unique ID (UUID) set to true.

:ref:``

1..1

localId

Locally used identifier unique with a specified context, such as a variable name within a dataset.

LocalIdFormat

0..*

version

Version number of the object.

:ref:``

1..1

versionDate

Date and time the object was changed expressed in standard ISO formats.

XSDdate

0..1

versionRationale

Reason for making a new version of the object.

RationaleDefinition

0..1

versionResponsibility

Contributor who has the ownership and responsibility for the current version.

:ref:``

0..1

Associations

Multiplicity

Association

Navigable Class

Multiplicity

0..*

Unit_has_UnitType

UnitType

0..*

TBD

Diagram

TBD