| ddi_usage {rddi} | R Documentation |
usage and its child nodes
Description
Defines where in the instance the controlled vocabulary which is identified is utilized. A controlled vocabulary may occur either in the content of an element or in an attribute on an element. The usage can either point to a collection of elements using an XPath via the selector element or point to a more specific collection of elements via their identifier using the specificElements element. If the controlled vocabulary occurs in an attribute within the element, the attribute element identifies the specific attribute. When specific elements are specified, an authorized code value may also be provided. If the current value of the element or attribute identified is not in the controlled vocabulary or is not identical to a code value, the authorized code value identifies a valid code value corresponding to the meaning of the content in the element or attribute. More information on this element, especially the allowed attributes, can be found in the references.
Usage
ddi_usage(...)
ddi_attribute(...)
ddi_selector(...)
ddi_specificElements(...)
Arguments
... |
Child nodes or attributes. |
Details
Parent nodes
usage is contained in controlledVocabUsed.
usage specific child nodes
-
ddi_attribute()identifies an attribute within the element(s) identified by the selector or specificElements in which the controlled vocabulary is used. The fully qualified name used here must correspond to that in the instance, which is to say that if the attribute is namespace qualified, the prefix used here must match that which is defined in the instance. -
ddi_selector()identifies a collection of elements in which a controlled vocabulary is used. This is a simplified XPath which must correspond to the actual instance in which it occurs, which is to say that the fully qualified element names here must correspond to those in the instance. This XPath can only identify elements and does not allow for any predicates. The XPath must either be rooted or deep. -
ddi_specificElements()identifies a collection of specific elements via their identifiers in the refs attribute, which allows for a tokenized list of identifier values which must correspond to identifiers which exist in the instance. The authorizedCodeValue attribute can be used to provide a valid code value corresponding to the meaning of the content in the element or attribute when the identified element or attribute does not use an actual valid value from the controlled vocabulary.
Value
A ddi_node object.
References
specificElements documentation
Examples
ddi_usage(ddi_selector("/codeBook/stdyDscr/method/dataColl/timeMeth"))
ddi_usage(ddi_selector("/codeBook/stdyDscr/method/dataProcessing"), ddi_attribute("type"))
ddi_usage(ddi_specificElements(refs = "ICPSR4328timeMeth", authorizedCodeValue = "CrossSection"))