Module search_parameter_cardinality 

Search parameters that produce at most one index value per resource.

@generated by bash scripts/search_param_cardinality_build.sh — do not edit.

A parameter listed here for a resource type selects at most one value from a resource of that type, and converts it to at most one index entry, so it can be stored as a scalar column, which is what lets an index answer an ordered comparison, a prefix match or a sort. The answer is per type: a shared parameter like clinical-patient takes one branch of its union per type, and can be single for some and repeating for others.

Absence means “not known to be single”. A parameter whose expression needs the FHIRPath engine to resolve, or that the schema walk could not follow, is absent for the same reason a genuinely repeating one is: storing several values in a scalar column keeps the first and drops the rest.

Functions

is_single_valued

Whether the parameter url produces at most one index value for a resource of type resource_type — as a parameter of that type, or of every type (Resource, DomainResource).