entity.constraint.cardinality

NCEAS / metadig-checks

MetaDIG suites and checks for data and metadata improvement and guidance.

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entity.constraint.cardinality #42

Open gothub opened 5 years ago

gothub commented 5 years ago

Description

Check the cardinality of the entity integrity constraints.

Priority

FAIR: Optional

Issues

ISO 19115 doesn't have this concept

Procedure

For each foreign key among entities in the data set, is the cardinality of the relationship specified as *, +, or {m,n}?.

iamchrisser commented 5 years ago

ISO has a concept like this in 19110 - Methodology for Feature Cataloging. For each attribute defined (in an FC_Attribute block) this information can be represented using the 'cardinality' element, which has value type gco:multiplicity, which is represented as a gco:range block. See below. `

1 1 ` from: http://www.datypic.com/sc/niem21/e-gco_range-1.html 'Optional' is the right level of requirement for this, I think. Although maybe this is not the same concept. I'm not as familiar with EML.

gothub commented 5 years ago

From the FAIR workshop at NCEAS:

... this really represents multiple checks, one for each of the integrity constraints that can 
be expressed, including primary key, foreign key, unique key, check constraint, not null 
constraint, join condition.  For each of these, there are two checks -- one is whether the 
check has been specified in metadata, the second if the data in the dataset is congruent
with those constraints. 

See: https://github.com/NCEAS/eml/blob/master/eml-constraint.png