ERD

erDiagram
  mkb_mapping_ethnicity {
    snomed_concept_id VARCHAR PK
    snomed_description_id VARCHAR FK
    emis_code_id VARCHAR FK
  }

  snomed_description {
    snomed_description_id VARCHAR PK
  }

  clinical_code {
    emis_code_id VARCHAR PK
  }

  mkb_mapping_ethnicity }|--|{ snomed_description : "has_description"
  mkb_mapping_ethnicity }|--|{ clinical_code : "maps_to_code"