Purpose

The 900000000000456007 $$ Reference set descriptor $$ is a reference set that used to specify the format of all reference sets included in a release. The data type and meaning of the referenced component and each additional field within each reference set is described by this reference set .
Reference set descriptor can be used to define

• The order of appearance of additional attributes (other than those mandatory for all reference sets );
• The name and purpose of the additional attributes;
• The data types for the additional attributes.

This allows for a reference set to be validated using the metadata embedded within the reference set descriptor in the following ways:

• the data type of its attributes may be validated against the data type declared in the reference set descriptor;
• the column order can be checked against the reference set descriptor.

Data structure

The Reference set descriptor reference set is a Component - Component - Integer reference set that specifies the structure of reference sets. Its structure is shown in the following table.

At least one row must exist for each reference set included in a release. This row must have an attributeOrder value of '0' and an attributeType of ' component type' (or one of its descendants). The referencedComponentId identifies the reference set defined by the descriptor.
There is one additional row for each additional column present in the specified reference set .
Creation of Reference set descriptor data is mandatory when creating a new reference set in the International Release or in a National Extension .
Creation of a Reference set descriptor is optional when creating a reference set in another Extension. If a descriptor is not created, the descriptor of the closest ancestor of the reference set is used when validating reference set member records.

Metadata

The following metadata in the |Foundation metadata concept | hierarchy supports the reference set descriptor reference set .
The Reference Set Descriptor Reference Set is specified by the 900000000000456007 $$ Reference set descriptor $$ concept in the metadata hierarchy.

• 900000000000441003 $$ SNOMED CT Model Component $$
  • 900000000000454005 $$ Foundation metadata concept $$
    • 900000000000455006 $$ Reference set $$
      • 900000000000456007 $$ Reference set descriptor $$

Figure 6. Reference Set Descriptor Concept in the Metadata Hierarchy
Values in the Reference Set are populated from:

• 900000000000454005 $$ Foundation metadata concept $$
  • 900000000000457003 $$ Reference set attribute $$
    • 900000000000458008 $$ Attribute description $$
    • 900000000000459000 $$ Attribute type $$
      • 900000000000460005 $$ Component type $$
        • 900000000000461009 $$ Concept type component $$
        • 900000000000462002 $$ Description type component $$
        • 900000000000463007 $$ Relationship type component $$
        • 900000000000464001 $$ Reference set member type component $$
      • 900000000000465000 $$ String $$
        • 900000000000466004 $$ Text $$
          • 900000000000467008 $$ Single character $$
          • 900000000000468003 $$ Text < 256 bytes $$
        • 900000000000469006 $$ URL $$
          • 900000000000470007 $$ HTML reference $$
          • 900000000000471006 $$ Image reference $$ ...
        • 900000000000474003 $$ UUID $$
        • 900000000000475002 $$ Time $$
      • 900000000000476001 $$ Integer $$
        • 900000000000477005 $$ Signed integer $$
        • 900000000000478000 $$ Unsigned integer $$
      • 900000000000460005 $$ Component type $$ ...
      • 900000000000465000 $$ String $$ ...
      • 900000000000476001 $$ Integer $$ ...
    • 900000000000479008 $$ Attribute order $$
    • 900000000000491004 $$ Attribute value $$ ...

Figure 7. Reference Set Attribute Metadata Hierarchy

Descriptor

The table below shows the descriptor that defines the structure of the 900000000000456007 $$ Reference set descriptor $$ .

Note: The table above omits the initial four columns of data present in the release file. These follow the standards versioning pattern id, effectiveTime, active, moduleId. Additionally, to aid understanding, the table above also includes the term from one of the descriptions associated with each of the identified concept. The release file only contains the identifier .