All Attributes of entities in a Substance Administration Query Information Model shall be specified both as a Matching Key Attribute (either required or optional) and as a Return Key Attribute.
The Matching Key Attributes are Keys, which select Query items to be included in a requested Query.
A Substance Administration Query Service SCP shall support matching based on values of all Required Matching Key Attributes of the C-FIND request.
In the Substance Administration Query Information Model, a set of Attributes may be defined as Optional Matching Key Attributes. Optional Matching Key Attributes contained in the Identifier of a C-FIND request may induce two different types of behavior depending on support for matching by the SCP. If the SCP
— does not support matching on the Optional Matching Key Attribute, then the Optional Matching Key Attribute shall be ignored for matching but shall be processed in the same manner as a Return Key Attribute.
— supports matching of the Optional Matching Key Attribute, then the Optional Matching Key Attribute shall be processed in the same manner as a Required Matching Key.
Notes: 1. The Conformance Statement of the SCP lists the Optional Matching Key Attributes that are supported for matching.
2. An SCU can not expect the SCP to support a match on an Optional Matching Key.
The values of Return Key Attributes to be retrieved with the Query are specified with zero-length (universal matching) in the C-FIND request. SCPs shall support Return Key Attributes defined by a Substance Administration Query Information Model according to the Data Element Type (1, 1C, 2, 2C, 3) as defined in PS 3.5.
Every Matching Key Attribute shall also be considered as a Return Key Attribute. Therefore the C-FIND response shall contain, in addition to the values of the requested Return Key Attributes, the values of the requested Matching Key Attributes.
Notes: 1 The Conformance Statement of the SCP lists the Return Key Attributes of Type 3 that are supported.
2. An SCU may choose to supply any subset of Return Key Attributes.
3. An SCU can not expect to receive any Type 3 Return Key Attributes.
4. Return Key attributes with VR of SQ may be specified either with zero-length, or with a zero-length item in the sequence.