3.1 KiB
3.1 KiB
The CONCEPT_RELATIONSHIP table contains records that define direct relationships between any two Concepts and the nature or type of the relationship. Each type of a relationship is defined in the RELATIONSHIP table.
| Field | Required | Type | Description |
|---|---|---|---|
| concept_id_1 | Yes | integer | A foreign key to a Concept in the CONCEPT table associated with the relationship. Relationships are directional, and this field represents the source concept designation. |
| concept_id_2 | Yes | integer | A foreign key to a Concept in the CONCEPT table associated with the relationship. Relationships are directional, and this field represents the destination concept designation. |
| relationship_id | Yes | varchar(20) | A unique identifier to the type or nature of the Relationship as defined in the RELATIONSHIP table. |
| valid_start_date | Yes | date | The date when the instance of the Concept Relationship is first recorded. |
| valid_end_date | Yes | date | The date when the Concept Relationship became invalid because it was deleted or superseded (updated) by a new relationship. Default value is 31-Dec-2099. |
| invalid_reason | No | varchar(1) | Reason the relationship was invalidated. Possible values are 'D' (deleted), 'U' (replaced with an update) or NULL when valid_end_date has the default value. |
Conventions
- Relationships can generally be classified as hierarchical (parent-child) or non-hierarchical (lateral).
- All Relationships are directional, and each Concept Relationship is represented twice symmetrically within the CONCEPT_RELATIONSHIP table. For example, the two SNOMED concepts of 'Acute myocardial infarction of the anterior wall' and 'Acute myocardial infarction' have two Concept Relationships: 1- 'Acute myocardial infarction of the anterior wall' 'Is a' 'Acute myocardial infarction', and 2- 'Acute myocardial infarction' 'Subsumes' 'Acute myocardial infarction of the anterior wall'.
- There is one record for each Concept Relationship connecting the same Concepts with the same relationship_id.
- Since all Concept Relationships exist with their mirror image (concept_id_1 and concept_id_2 swapped, and the relationship_id replaced by the reverse_relationship_id from the RELATIONSHIP table), it is not necessary to query for the existence of a relationship both in the concept_id_1 and concept_id_2 fields.
- Concept Relationships define direct relationships between Concepts. Indirect relationships through 3rd Concepts are not captured in this table. However, the CONCEPT_ANCESTOR table does this for hierachical relationships over several "generations" of direct relationships.
- In previous versions of the CDM, the relationship_id used to be a numerical identifier. See the RELATIONSHIP table.