This extension defines a possible search parameter combination by listing a set of search parameters and indicating whether they are required or optional.

• If a search combination is specified, clients should expect that they must submit a search that meets one of the required combinations or the search will be unsuccessful.
• If multiple search parameter combinations are specified, a client may pick between them, and supply the minimal required parameters for any of the combinations.
• If no parameters in the set of search parameters are listed as required, then at least one of the listed optional parameters must be present. This shorthand method is the same as repeating the entire extension for each combination of optional and required search parameters.

For example, on the Patient Resource you could use this to state support for searching by Patient.name and Patient.gender is required.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

• unordered
• Open
• discriminators: value:url

A search parameter name in the combination which is required.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

An Extension

• unordered
• Open
• discriminators: value:url

Source of the definition for the extension code - a logical name or a URL.

The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.

Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

A search parameter name in the combination which is optional.

If a defined parameter is not listed as a required or optional parameter, the implication is that the parameter is not supported with this combination. Servers may ignore It, though some may return an error if it is used.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

An Extension

• unordered
• Open
• discriminators: value:url

Source of the definition for the extension code - a logical name or a URL.

The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.

Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

Source of the definition for the extension code - a logical name or a URL.

The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.

Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).