Get Relationship Types

curl "https://api.omophub.com/v1/relationships/types?page_size=50" \
  -H "Authorization: Bearer YOUR_API_KEY"

import requests

url = "https://api.omophub.com/v1/relationships/types"
params = {"page_size": 50}
headers = {"Authorization": "Bearer YOUR_API_KEY"}

response = requests.get(url, params=params, headers=headers)
data = response.json()

print(f"Total relationship types: {data['meta']['pagination']['total_items']}")
for rel_type in data['data']['relationship_types']:
    hierarchical = "Yes" if rel_type['is_hierarchical'] == '1' else "No"
    print(f"  {rel_type['relationship_id']} -> {rel_type['reverse_relationship_id']} (Hierarchical: {hierarchical})")

import { OMOPHub } from '@omophub/omophub-node';

const client = new OMOPHub();
const { data, meta } = await client.relationships.types({ pageSize: 50 });
console.log(`Found ${meta?.pagination?.total_items} relationship types`);

data?.relationship_types.forEach(type => {
  console.log(`${type.relationship_id} <-> ${type.reverse_relationship_id}`);
});

{
  "success": true,
  "data": {
    "relationship_types": [
      {
        "relationship_id": "Is a",
        "relationship_name": "Is a",
        "is_hierarchical": "1",
        "defines_ancestry": "1",
        "reverse_relationship_id": "Subsumes",
        "relationship_concept_id": 44818821
      },
      {
        "relationship_id": "Maps to",
        "relationship_name": "Maps to",
        "is_hierarchical": "0",
        "defines_ancestry": "0",
        "reverse_relationship_id": "Mapped from",
        "relationship_concept_id": 44818981
      },
      {
        "relationship_id": "Has finding site",
        "relationship_name": "Has finding site",
        "is_hierarchical": "0",
        "defines_ancestry": "0",
        "reverse_relationship_id": "Finding site of",
        "relationship_concept_id": 44818788
      }
    ]
  },
  "meta": {
    "request_id": "req_abc123",
    "vocab_release": "2025.1",
    "pagination": {
      "page": 1,
      "page_size": 100,
      "total_items": 642,
      "total_pages": 7,
      "has_next": true,
      "has_previous": false
    }
  }
}

curl "https://api.omophub.com/v1/relationships/types?page_size=50" \
  -H "Authorization: Bearer YOUR_API_KEY"

import requests

url = "https://api.omophub.com/v1/relationships/types"
params = {"page_size": 50}
headers = {"Authorization": "Bearer YOUR_API_KEY"}

response = requests.get(url, params=params, headers=headers)
data = response.json()

print(f"Total relationship types: {data['meta']['pagination']['total_items']}")
for rel_type in data['data']['relationship_types']:
    hierarchical = "Yes" if rel_type['is_hierarchical'] == '1' else "No"
    print(f"  {rel_type['relationship_id']} -> {rel_type['reverse_relationship_id']} (Hierarchical: {hierarchical})")

import { OMOPHub } from '@omophub/omophub-node';

const client = new OMOPHub();
const { data, meta } = await client.relationships.types({ pageSize: 50 });
console.log(`Found ${meta?.pagination?.total_items} relationship types`);

data?.relationship_types.forEach(type => {
  console.log(`${type.relationship_id} <-> ${type.reverse_relationship_id}`);
});

{
  "success": true,
  "data": {
    "relationship_types": [
      {
        "relationship_id": "Is a",
        "relationship_name": "Is a",
        "is_hierarchical": "1",
        "defines_ancestry": "1",
        "reverse_relationship_id": "Subsumes",
        "relationship_concept_id": 44818821
      },
      {
        "relationship_id": "Maps to",
        "relationship_name": "Maps to",
        "is_hierarchical": "0",
        "defines_ancestry": "0",
        "reverse_relationship_id": "Mapped from",
        "relationship_concept_id": 44818981
      },
      {
        "relationship_id": "Has finding site",
        "relationship_name": "Has finding site",
        "is_hierarchical": "0",
        "defines_ancestry": "0",
        "reverse_relationship_id": "Finding site of",
        "relationship_concept_id": 44818788
      }
    ]
  },
  "meta": {
    "request_id": "req_abc123",
    "vocab_release": "2025.1",
    "pagination": {
      "page": 1,
      "page_size": 100,
      "total_items": 642,
      "total_pages": 7,
      "has_next": true,
      "has_previous": false
    }
  }
}

This endpoint returns all relationship types from the OMOP CDM RELATIONSHIP table, which defines the types of connections that can exist between concepts.

Query Parameters

page

integer

default:"1"

Page number for pagination (1-based)

page_size

integer

default:"100"

Number of relationship types to return per page (max 500)

vocab_release

string

Specific vocabulary release version
Example: 2025.1

Response

relationship_types

array

Array of relationship type objects from the OMOP CDM RELATIONSHIP table

Show Relationship Type Object

relationship_id

string

Unique identifier for the relationship type (e.g., “Is a”, “Maps to”)

relationship_name

string

Display name of the relationship type

is_hierarchical

string

Whether this relationship creates hierarchical structure (“0” or “1”)

defines_ancestry

string

Whether this relationship is used in CONCEPT_ANCESTOR computation (“0” or “1”)

reverse_relationship_id

string

The relationship_id of the reverse relationship (e.g., “Subsumes” for “Is a”)

relationship_concept_id

integer

Concept ID representing this relationship type in the CONCEPT table

meta

object

Response metadata including pagination

Show Metadata Object

pagination

object

page

integer

Current page number

page_size

integer

Items per page

total_items

integer

Total relationship types

total_pages

integer

Total number of pages

has_next

boolean

Whether next page exists

has_previous

boolean

Whether previous page exists

request_id

string

Unique request identifier

vocab_release

string

Vocabulary release version used

curl "https://api.omophub.com/v1/relationships/types?page_size=50" \
  -H "Authorization: Bearer YOUR_API_KEY"

import requests

url = "https://api.omophub.com/v1/relationships/types"
params = {"page_size": 50}
headers = {"Authorization": "Bearer YOUR_API_KEY"}

response = requests.get(url, params=params, headers=headers)
data = response.json()

print(f"Total relationship types: {data['meta']['pagination']['total_items']}")
for rel_type in data['data']['relationship_types']:
    hierarchical = "Yes" if rel_type['is_hierarchical'] == '1' else "No"
    print(f"  {rel_type['relationship_id']} -> {rel_type['reverse_relationship_id']} (Hierarchical: {hierarchical})")

import { OMOPHub } from '@omophub/omophub-node';

const client = new OMOPHub();
const { data, meta } = await client.relationships.types({ pageSize: 50 });
console.log(`Found ${meta?.pagination?.total_items} relationship types`);

data?.relationship_types.forEach(type => {
  console.log(`${type.relationship_id} <-> ${type.reverse_relationship_id}`);
});

{
  "success": true,
  "data": {
    "relationship_types": [
      {
        "relationship_id": "Is a",
        "relationship_name": "Is a",
        "is_hierarchical": "1",
        "defines_ancestry": "1",
        "reverse_relationship_id": "Subsumes",
        "relationship_concept_id": 44818821
      },
      {
        "relationship_id": "Maps to",
        "relationship_name": "Maps to",
        "is_hierarchical": "0",
        "defines_ancestry": "0",
        "reverse_relationship_id": "Mapped from",
        "relationship_concept_id": 44818981
      },
      {
        "relationship_id": "Has finding site",
        "relationship_name": "Has finding site",
        "is_hierarchical": "0",
        "defines_ancestry": "0",
        "reverse_relationship_id": "Finding site of",
        "relationship_concept_id": 44818788
      }
    ]
  },
  "meta": {
    "request_id": "req_abc123",
    "vocab_release": "2025.1",
    "pagination": {
      "page": 1,
      "page_size": 100,
      "total_items": 642,
      "total_pages": 7,
      "has_next": true,
      "has_previous": false
    }
  }
}

Usage Examples

All Relationship Types

Get all available relationship types:

curl "https://api.omophub.com/v1/relationships/types" \
  -H "Authorization: Bearer YOUR_API_KEY"

Paginated Results

Navigate through pages of relationship types:

curl "https://api.omophub.com/v1/relationships/types?page=2&page_size=50" \
  -H "Authorization: Bearer YOUR_API_KEY"

Get Concept Relationships - Relationships for specific concepts
Get Concept Mappings - Cross-vocabulary mappings
Get Vocabularies - Available vocabularies

Notes

Relationship types come from the OMOP CDM RELATIONSHIP table
All relationships exist symmetrically (both directions)
Hierarchical relationships (like “Is a”) are used to build the CONCEPT_ANCESTOR table
The defines_ancestry field indicates which relationships contribute to ancestor computation
Each relationship type has a corresponding concept in the CONCEPT table

Resolve FHIR CodeableConcept List Relationships for a Concept

API Reference

Search

Concepts

Concept Hierarchy

Mappings

FHIR Resolver

Relationships

Domains & Classifications

Vocabularies

Query Parameters

Response

Usage Examples

All Relationship Types

Paginated Results

Notes

​Query Parameters

​Response

​Usage Examples

​All Relationship Types

​Paginated Results

​Related Endpoints

​Notes

Query Parameters

Response

Usage Examples

All Relationship Types

Paginated Results

Related Endpoints

Notes