> ## Documentation Index
> Fetch the complete documentation index at: https://docs.getmembrane.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Universal Data Models

Universal Data Models provided by connector map its collections to [Universal Data Models](/reference/workspace-elements/connectors/universal-data-models) and back.

They are stored in `udm.yml` file in the connector.

Example:

```yaml theme={null}
contacts: # Universal data model
  collectionMappings: # How it maps to data collections in connector
    - key: contacts # Collection it maps to
      fieldsFromCollection: # Mapping from collection fields to UDM (using formulas)
        id:
          $var: $.id
        fullName:
          $concat:
            values:
              - $var: $.firstName
              - $var: $.lastName
            delimiter: ' '
        firstName:
          $var: $.firstName
        lastName:
          $var: $.lastName
        # ... more mappings
      fieldsToCollection: # Mapping from UDM fields to collection fields
        id:
          $var: $.id
        firstName:
          $var: $.firstName
        lastName:
          $var: $.lastName
        # ... more mappings
```