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.
|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|valid_end_date||Yes||date||The date when the Concept Relationship became invalid because it was deleted or superseded (updated) by a new relationship.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.|