Concept Relationship

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	FK Table	Description
concept_id_1	Yes	bigint	CONCEPT	A foreign key to a Concept associated with the relationship. Relationships are directional, and this field represents the source concept designation.
concept_id_2	Yes	bigint	CONCEPT	A foreign key to a Concept associated with the relationship. Relationships are directional, and this field represents the destination concept designation.
relationship_id	Yes	varchar(20)	RELATIONSHIP	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valid_end_date	Yes	date		The date when the Concept Relationship became invalid because it was deleted or superseded (updated) by a new relationship.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 hierarchical 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.